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wild to cultivated changes?
This is not off topic even though the beginning may sound like it is, so
please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
with regard to wolfs, cats and dogs, a word to learn about is neoteny. Used
with domestic cats and dogs the idea is that adult cats and dogs retain a lot of personality traits common only to the puppies and kittens of similar wild species. I guess it has made them easier to handle over the long generations they have been associating with people. I saw a science show on the Discovery channel once when I couldn't find a channel showing Star Trek reruns. Big subject with regard to orchid species judging. A lot of wild orchids can't hold a candle to their line-bred cousins in captivity with regard to judging standards. Judges are taught to consider the species normal habit when judging it, but the process can almost not help but include certain pre-judgments of what a beautiful flower looks like. Flame me, it's okay. I can handle it. "Orchids that have been bred in captivity for generations grow better in pots than wild ones." That's quote but not mine. :-) Smart breeders do not use plants for breeding if they are prone to disease, so one would think that domestic populations that are generations old might be more disease resistant. On the other hand, the environment we provide for them is so protected that one would also thing they would not live long if some well meaning person were to repatriate them into their native habitat. I'll bet you get lots of replies to this topic. Al ne·ot·e·ny NOUN:1. Retention of juvenile characteristics in the adults of a species. 2. The attainment of sexual maturity by an organism still in its larval stage. J Fortuna" wrote in message ... This is not off topic even though the beginning may sound like it is, so please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
with regard to wolfs, cats and dogs, a word to learn about is neoteny. Used
with domestic cats and dogs the idea is that adult cats and dogs retain a lot of personality traits common only to the puppies and kittens of similar wild species. I guess it has made them easier to handle over the long generations they have been associating with people. I saw a science show on the Discovery channel once when I couldn't find a channel showing Star Trek reruns. Big subject with regard to orchid species judging. A lot of wild orchids can't hold a candle to their line-bred cousins in captivity with regard to judging standards. Judges are taught to consider the species normal habit when judging it, but the process can almost not help but include certain pre-judgments of what a beautiful flower looks like. Flame me, it's okay. I can handle it. "Orchids that have been bred in captivity for generations grow better in pots than wild ones." That's quote but not mine. :-) Smart breeders do not use plants for breeding if they are prone to disease, so one would think that domestic populations that are generations old might be more disease resistant. On the other hand, the environment we provide for them is so protected that one would also thing they would not live long if some well meaning person were to repatriate them into their native habitat. I'll bet you get lots of replies to this topic. Al ne·ot·e·ny NOUN:1. Retention of juvenile characteristics in the adults of a species. 2. The attainment of sexual maturity by an organism still in its larval stage. J Fortuna" wrote in message ... This is not off topic even though the beginning may sound like it is, so please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
with regard to wolfs, cats and dogs, a word to learn about is neoteny. Used
with domestic cats and dogs the idea is that adult cats and dogs retain a lot of personality traits common only to the puppies and kittens of similar wild species. I guess it has made them easier to handle over the long generations they have been associating with people. I saw a science show on the Discovery channel once when I couldn't find a channel showing Star Trek reruns. Big subject with regard to orchid species judging. A lot of wild orchids can't hold a candle to their line-bred cousins in captivity with regard to judging standards. Judges are taught to consider the species normal habit when judging it, but the process can almost not help but include certain pre-judgments of what a beautiful flower looks like. Flame me, it's okay. I can handle it. "Orchids that have been bred in captivity for generations grow better in pots than wild ones." That's quote but not mine. :-) Smart breeders do not use plants for breeding if they are prone to disease, so one would think that domestic populations that are generations old might be more disease resistant. On the other hand, the environment we provide for them is so protected that one would also thing they would not live long if some well meaning person were to repatriate them into their native habitat. I'll bet you get lots of replies to this topic. Al ne·ot·e·ny NOUN:1. Retention of juvenile characteristics in the adults of a species. 2. The attainment of sexual maturity by an organism still in its larval stage. J Fortuna" wrote in message ... This is not off topic even though the beginning may sound like it is, so please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
Al wrote:
"Orchids that have been bred in captivity for generations grow better in pots than wild ones." That's quote but not mine. :-) Smart breeders do not use plants for breeding if they are prone to disease, so one would think that domestic populations that are generations old might be more disease resistant. On the other hand, the environment we provide for them is so protected that one would also thing they would not live long if some well meaning person were to repatriate them into their native habitat. I'll bet you get lots of replies to this topic. I'll bite... Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Virtually all of them... Any cattleya which has been in captivity for more than a couple generations is quite different from its wild cousins. If nothing else, many breeders have intentionally converted them to tetraploid. Line bred Phal 'aphrodite' (quotes mine, because it is likely that the line bred ones have some hybrid background) are very distinct from wild ones. Doritis pulcherrima is quite cute in its native form, but you couldn't get one awarded today, as the line bred ones have flowers that are several times bigger. There is some debate in judging circles as to whether this is 'fair'. No, it isn't fair if you are a wonderful wild collected flower and competing against a line bred specimen. Sorry. But we don't grow orchids to be fair, we grow them for nice flowers. Why is line breeding so different than nature's breeding? Human selection is different than natural selection. For example, if we see an albino flower (and like it) we 'fix' the phenotype. Orchids are designed to cross pollinate, not self pollinate. So, since you get a copy of each gene (allele) from your parents, the albinistic allele can be masked or diluted by the normal allele from the other parent. But humans are persistant, and we will self that albino flower to try to get offspring which are homozygous for the albinistic allele. Once we do that, the phenotype is 'fixed'. In other words, if we self that albino offspring, we can only get albino offspring. Natural selection would have diluted that trait in the gene pool, since the vast majority of potential mates have the gene for 'normal' color. Anyway, we can do that for any trait. The human selection process is actively directed, natural selection is not. This is why we have terriers and St. Bernards - somebody wanted little dogs and somebody else wanted big dogs, and selected appropriately. We've been mucking about with everything for a long time. I bet you've never seen the wild maize that our modern maize is bred from, and if you did you probably wouldn't recognize it. Orchid breeders select for features they like (vigor is certainly one of those), and don't breed with plants which have 'inferior' features. One of the features that we absolutely must select for is growth in captivity. If the plant can't grow from seed to bloom, it can't be bred with. So we have no choice but to select for plants that grow well in flask and pots. Wild collected plants are often difficult to get 'viable' seed (seed that grows in flasks, anyway) from, but once you get to the next generation, it is almost always much easier. Anyway, don't buy jungle collected plants. They are of absolutely no use to the hobby orchid grower. They will not be 'better' (whatever that means) than domesticated ones. That is not to say that they aren't valuable from a genetic diversity standpoint. If you have bred all the color out of your captive plants, you can't get it back unless you have a wild plant which has the alleles for it. Line breeding is a one way street. Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
That was a wonderful Nova program, wasn't it!! Made me start wondering about
the same thing. I know Alexis Pardo Isla once said that the orchids we grow are selected for those that will grow in flasking medium. So that would be a basic difference between those we have in captivity and the wild type. K Barrett "J Fortuna" wrote in message ... This is not off topic even though the beginning may sound like it is, so please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
"Rob Halgren" wrote in message
... Al wrote: "Orchids that have been bred in captivity for generations grow better in pots than wild ones." That's quote but not mine. :-) Smart breeders do not use plants for breeding if they are prone to disease, so one would think that domestic populations that are generations old might be more disease resistant. On the other hand, the environment we provide for them is so protected that one would also thing they would not live long if some well meaning person were to repatriate them into their native habitat. I'll bet you get lots of replies to this topic. I'll bite... Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Virtually all of them... Any cattleya which has been in captivity for more than a couple generations is quite different from its wild cousins. If nothing else, many breeders have intentionally converted them to tetraploid. Line bred Phal 'aphrodite' (quotes mine, because it is likely that the line bred ones have some hybrid background) are very distinct from wild ones. Doritis pulcherrima is quite cute in its native form, but you couldn't get one awarded today, as the line bred ones have flowers that are several times bigger. There is some debate in judging circles as to whether this is 'fair'. No, it isn't fair if you are a wonderful wild collected flower and competing against a line bred specimen. Sorry. But we don't grow orchids to be fair, we grow them for nice flowers. Why is line breeding so different than nature's breeding? Human selection is different than natural selection. For example, if we see an albino flower (and like it) we 'fix' the phenotype. Orchids are designed to cross pollinate, not self pollinate. So, since you get a copy of each gene (allele) from your parents, the albinistic allele can be masked or diluted by the normal allele from the other parent. But humans are persistant, and we will self that albino flower to try to get offspring which are homozygous for the albinistic allele. Once we do that, the phenotype is 'fixed'. In other words, if we self that albino offspring, we can only get albino offspring. Natural selection would have diluted that trait in the gene pool, since the vast majority of potential mates have the gene for 'normal' color. Anyway, we can do that for any trait. The human selection process is actively directed, natural selection is not. This is why we have terriers and St. Bernards - somebody wanted little dogs and somebody else wanted big dogs, and selected appropriately. We've been mucking about with everything for a long time. I bet you've never seen the wild maize that our modern maize is bred from, and if you did you probably wouldn't recognize it. Orchid breeders select for features they like (vigor is certainly one of those), and don't breed with plants which have 'inferior' features. One of the features that we absolutely must select for is growth in captivity. If the plant can't grow from seed to bloom, it can't be bred with. So we have no choice but to select for plants that grow well in flask and pots. Wild collected plants are often difficult to get 'viable' seed (seed that grows in flasks, anyway) from, but once you get to the next generation, it is almost always much easier. Anyway, don't buy jungle collected plants. They are of absolutely no use to the hobby orchid grower. They will not be 'better' (whatever that means) than domesticated ones. That is not to say that they aren't valuable from a genetic diversity standpoint. If you have bred all the color out of your captive plants, you can't get it back unless you have a wild plant which has the alleles for it. Line breeding is a one way street. Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit There was an interesting comment in the Nova (PBS) program about how line breeding in dogs makes them more susceptible to viruses and cancers, something I've always heard, but never understood. Anyway, your comment and one by Peter O'Byrne about how line breeding and hybrid lines in what are supposedly species makes me wonder. How identical *is* species DNA anyway? Is the genome like a template? If one could put the entire DNA strands of a species on an overhead projector acetate, could one overlay all the G-C and A-T base pairs on top of one another would they all line up? Could you say that any variation within that line-up would be something like 'different colored eyes, and so same species' or 'different all together and so a hybrid'? I mean, how can one isolate individual variation within a species? And how would one know that the aberrant base pairs weren't individual variation but the result of hybridization? Who is to say what species DNA is? Lord knows there's enough bickering and infighting amongst taxonomists who classify species according to set international rules. Who would be the agency that would determine and stamp approve what 'species DNA' looks like? And how would they know? What if they missed a few individuals? Like if a Greater Alien Space Race came to the Earth they'd think by preponderance of numbers that the human species was Asian, and take that DNA as criteria of human-ness. The tiny Bushman from the Kalihari Desert would be shit out of luck because they don't look Asian. What then? Would The Aliens be justified in eating Bushmen because, according to their definition of human-ness, they weren't human? K Barrett |
wild to cultivated changes?
"K Barrett" wrote in message news:xGQUb.186854$sv6.989995@attbi_s52... [snip] How identical *is* species DNA anyway? This question gets quite close to the real issue. If rephrased to be, "Are the genomes of two specimens of a given species identical," the answer must be no unless the two specimens represent clones of the same organism. The reason for this is that either the genome possessed by a given individual is identical to that possessed by another organism of the same species or it isn't. What both your question and my alteration of it presuppose we know what a species is and how to determine whether or not two arbitrary specimens are of the same species. Given some idea of what a species is, however, a more useful question would be, "How similar are the genomes possessed by any two individuals of a given species likely to be?" That is, in fact, something that can be quantified. Only clones (including all products of asexual reproduction but including also identical twins - the products of a natural cloning process if you like) will have identical genetic material. Modern taxonomy is based on measures of similarity, not judgements that two given specimens are identical. The more fundamental question, which must be answered FIRST, is "What is a species?" Without an answer to that question, it is not possible to form rational judgements on any other taxonomic issue. And there is no such definition in widespread use by taxonomists and that is the primary reason why modern taxonomy is in such a mess; much to the chagrin of other biologists and of horticulturalists alike. It is useful to observe that, among the cases of which I am aware, it only takes tiny genetic differences, in terms of percentage of genes having different alleles, to produce enormous differences in phenotype (the consequence of gene expression). The genetic material possessed by the Inuit (also known as eskimos - to the best of my knowledge, they prefer to be called Inuit), Dene, african bushmen and indoeuropeans is so similar, it would be both difficult and tedious to measure the differences to an acceptable degree of precision, and yet look at the diversity the existing differences make in their respective phenotypes. Does this help? Cheers, Ted |
wild to cultivated changes?
How identical *is* species DNA anyway? Is the genome like a template? If one could put the entire DNA strands of a species on an overhead projector acetate, could one overlay all the G-C and A-T base pairs on top of one another would they all line up? Could you say that any variation within that line-up would be something like 'different colored eyes, and so same species' or 'different all together and so a hybrid'? I mean, how can one isolate individual variation within a species? And how would one know that the aberrant base pairs weren't individual variation but the result of hybridization? This _is_ actually my field, for once... And yes, the genome is a template, if you aligned all of the DNA for all of the individuals in a species, it would line up pretty darn well. The last estimate I heard for the human genome was one SNP (single nucleotide polymorphism) for every 1000 bases or so. Not every SNP (in fact very few) actually does anything significant to a gene. We don't know enough now to read the genome quite like a book. The main problem is that there are very few single locus traits, most are multiple loci working in various degrees of collaboration. It isn't easy to read a book when the sentences bounce around between chapters and the grammar isn't entirely worked out. How do you know the difference between individual variation and hybridization? In a grossly oversimplified view: Most of the genes for two closely related species will be very close in sequence. This is as it should be, if they are derived from a common ancestor. But, if you look at the right genes, there should be a consistent difference in the sequence between two species. If you know that difference, then it is easy to look and see if an organism has two copies of organism A's gene, two copies of organism B's gene, or one of each. You need to look at many different genes, usually. Actually, a variation of this is exactly how a paternity test works (children are hybrids too). Note that is only the closely related things that we have a problem with... We can all tell that Paph. rothschildianum and Paph. armeniacum are distinct species. We can get a pretty good idea that Paph. Dollgoldii is a hybrid. We don't need DNA evidence for that... Who is to say what species DNA is? Lord knows there's enough bickering and infighting amongst taxonomists who classify species according to set international rules. Who would be the agency that would determine and stamp approve what 'species DNA' looks like? And how would they know? What if they missed a few individuals? Like if a Greater Alien Space Race came to the Earth they'd think by preponderance of numbers that the human species was Asian, and take that DNA as criteria of human-ness. The tiny Bushman from the Kalihari Desert would be shit out of luck because they don't look Asian. What then? Would The Aliens be justified in eating Bushmen because, according to their definition of human-ness, they weren't human? I actually have a talk about this worked up for orchids... The answer is that there is no magic answer when you use DNA, any more than there is when you use phenotypic markers for taxonomy. But, you can get good estimates of how far apart things are. The boundaries are always a mess, and always will be. DNA is just another tool. A powerful tool. Somebody still needs to decide just how far apart is far enough to qualify as a separate species. What makes something a distinct species is genetic isolation and time. Given enough of each, you don't fancy science to tell them apart. It is those fuzzy edges that kick you in the head. When Al's aliens come to pick him up, they will realize that his DNA is 99.9999%+ similar to both the Kalihari bushman and the Eskimo. It is extraordinarily similar to that of a chimpanzee. It is remarkably similar (in both sequence and the organization of the genes on the chromosomes) to the DNA of a mouse. It is somewhat (disturbingly) similar to the sequence and organization of the genes on the chromosome of the zebra fish. The farther apart we get, the more difference there is, but there is still remarkable conservation. Besides, we all know that the aliens (or monsters) eat the cute, mysteriously underdressed girls, who get separated from their group of friends by strange plot twists. I learned that from the movies. Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
Give me a day or two to mull this over and ask (hopefully an intelligent)
question. Thanks for your response K "Ted Byers" wrote in message . .. "K Barrett" wrote in message news:xGQUb.186854$sv6.989995@attbi_s52... [snip] How identical *is* species DNA anyway? This question gets quite close to the real issue. If rephrased to be, "Are the genomes of two specimens of a given species identical," the answer must be no unless the two specimens represent clones of the same organism. The reason for this is that either the genome possessed by a given individual is identical to that possessed by another organism of the same species or it isn't. What both your question and my alteration of it presuppose we know what a species is and how to determine whether or not two arbitrary specimens are of the same species. Given some idea of what a species is, however, a more useful question would be, "How similar are the genomes possessed by any two individuals of a given species likely to be?" That is, in fact, something that can be quantified. Only clones (including all products of asexual reproduction but including also identical twins - the products of a natural cloning process if you like) will have identical genetic material. Modern taxonomy is based on measures of similarity, not judgements that two given specimens are identical. The more fundamental question, which must be answered FIRST, is "What is a species?" Without an answer to that question, it is not possible to form rational judgements on any other taxonomic issue. And there is no such definition in widespread use by taxonomists and that is the primary reason why modern taxonomy is in such a mess; much to the chagrin of other biologists and of horticulturalists alike. It is useful to observe that, among the cases of which I am aware, it only takes tiny genetic differences, in terms of percentage of genes having different alleles, to produce enormous differences in phenotype (the consequence of gene expression). The genetic material possessed by the Inuit (also known as eskimos - to the best of my knowledge, they prefer to be called Inuit), Dene, african bushmen and indoeuropeans is so similar, it would be both difficult and tedious to measure the differences to an acceptable degree of precision, and yet look at the diversity the existing differences make in their respective phenotypes. Does this help? Cheers, Ted |
wild to cultivated changes?
Give me a day or two to mull this over and ask (hopefully an intelligent)
question. Thanks for your response K "Ted Byers" wrote in message . .. "K Barrett" wrote in message news:xGQUb.186854$sv6.989995@attbi_s52... [snip] How identical *is* species DNA anyway? This question gets quite close to the real issue. If rephrased to be, "Are the genomes of two specimens of a given species identical," the answer must be no unless the two specimens represent clones of the same organism. The reason for this is that either the genome possessed by a given individual is identical to that possessed by another organism of the same species or it isn't. What both your question and my alteration of it presuppose we know what a species is and how to determine whether or not two arbitrary specimens are of the same species. Given some idea of what a species is, however, a more useful question would be, "How similar are the genomes possessed by any two individuals of a given species likely to be?" That is, in fact, something that can be quantified. Only clones (including all products of asexual reproduction but including also identical twins - the products of a natural cloning process if you like) will have identical genetic material. Modern taxonomy is based on measures of similarity, not judgements that two given specimens are identical. The more fundamental question, which must be answered FIRST, is "What is a species?" Without an answer to that question, it is not possible to form rational judgements on any other taxonomic issue. And there is no such definition in widespread use by taxonomists and that is the primary reason why modern taxonomy is in such a mess; much to the chagrin of other biologists and of horticulturalists alike. It is useful to observe that, among the cases of which I am aware, it only takes tiny genetic differences, in terms of percentage of genes having different alleles, to produce enormous differences in phenotype (the consequence of gene expression). The genetic material possessed by the Inuit (also known as eskimos - to the best of my knowledge, they prefer to be called Inuit), Dene, african bushmen and indoeuropeans is so similar, it would be both difficult and tedious to measure the differences to an acceptable degree of precision, and yet look at the diversity the existing differences make in their respective phenotypes. Does this help? Cheers, Ted |
wild to cultivated changes?
Thanks for your response. It'll take me a while to assimilate it (I know,
its futile...) But a follow up question is coming... after I've had a few more Cosmopolitans K "Rob Halgren" wrote in message ... How identical *is* species DNA anyway? Is the genome like a template? If one could put the entire DNA strands of a species on an overhead projector acetate, could one overlay all the G-C and A-T base pairs on top of one another would they all line up? Could you say that any variation within that line-up would be something like 'different colored eyes, and so same species' or 'different all together and so a hybrid'? I mean, how can one isolate individual variation within a species? And how would one know that the aberrant base pairs weren't individual variation but the result of hybridization? This _is_ actually my field, for once... And yes, the genome is a template, if you aligned all of the DNA for all of the individuals in a species, it would line up pretty darn well. The last estimate I heard for the human genome was one SNP (single nucleotide polymorphism) for every 1000 bases or so. Not every SNP (in fact very few) actually does anything significant to a gene. We don't know enough now to read the genome quite like a book. The main problem is that there are very few single locus traits, most are multiple loci working in various degrees of collaboration. It isn't easy to read a book when the sentences bounce around between chapters and the grammar isn't entirely worked out. How do you know the difference between individual variation and hybridization? In a grossly oversimplified view: Most of the genes for two closely related species will be very close in sequence. This is as it should be, if they are derived from a common ancestor. But, if you look at the right genes, there should be a consistent difference in the sequence between two species. If you know that difference, then it is easy to look and see if an organism has two copies of organism A's gene, two copies of organism B's gene, or one of each. You need to look at many different genes, usually. Actually, a variation of this is exactly how a paternity test works (children are hybrids too). Note that is only the closely related things that we have a problem with... We can all tell that Paph. rothschildianum and Paph. armeniacum are distinct species. We can get a pretty good idea that Paph. Dollgoldii is a hybrid. We don't need DNA evidence for that... Who is to say what species DNA is? Lord knows there's enough bickering and infighting amongst taxonomists who classify species according to set international rules. Who would be the agency that would determine and stamp approve what 'species DNA' looks like? And how would they know? What if they missed a few individuals? Like if a Greater Alien Space Race came to the Earth they'd think by preponderance of numbers that the human species was Asian, and take that DNA as criteria of human-ness. The tiny Bushman from the Kalihari Desert would be shit out of luck because they don't look Asian. What then? Would The Aliens be justified in eating Bushmen because, according to their definition of human-ness, they weren't human? I actually have a talk about this worked up for orchids... The answer is that there is no magic answer when you use DNA, any more than there is when you use phenotypic markers for taxonomy. But, you can get good estimates of how far apart things are. The boundaries are always a mess, and always will be. DNA is just another tool. A powerful tool. Somebody still needs to decide just how far apart is far enough to qualify as a separate species. What makes something a distinct species is genetic isolation and time. Given enough of each, you don't fancy science to tell them apart. It is those fuzzy edges that kick you in the head. When Al's aliens come to pick him up, they will realize that his DNA is 99.9999%+ similar to both the Kalihari bushman and the Eskimo. It is extraordinarily similar to that of a chimpanzee. It is remarkably similar (in both sequence and the organization of the genes on the chromosomes) to the DNA of a mouse. It is somewhat (disturbingly) similar to the sequence and organization of the genes on the chromosome of the zebra fish. The farther apart we get, the more difference there is, but there is still remarkable conservation. Besides, we all know that the aliens (or monsters) eat the cute, mysteriously underdressed girls, who get separated from their group of friends by strange plot twists. I learned that from the movies. Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
Kathy,
Actually I did not see the Nova program myself, just heard someone talk about it. Sometimes (like this one) I regret not having a TV antenna or cable. However, most of the time I think we've made a wise choice: I know if I had TV reception I would spend hours watching it, and then I couldn't spend all this time here on rgo, and read as many books as I do, etc. Joanna "K Barrett" wrote in message news:z6QUb.186773$sv6.989867@attbi_s52... That was a wonderful Nova program, wasn't it!! Made me start wondering about the same thing. I know Alexis Pardo Isla once said that the orchids we grow are selected for those that will grow in flasking medium. So that would be a basic difference between those we have in captivity and the wild type. K Barrett "J Fortuna" wrote in message ... This is not off topic even though the beginning may sound like it is, so please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
Kathy,
Actually I did not see the Nova program myself, just heard someone talk about it. Sometimes (like this one) I regret not having a TV antenna or cable. However, most of the time I think we've made a wise choice: I know if I had TV reception I would spend hours watching it, and then I couldn't spend all this time here on rgo, and read as many books as I do, etc. Joanna "K Barrett" wrote in message news:z6QUb.186773$sv6.989867@attbi_s52... That was a wonderful Nova program, wasn't it!! Made me start wondering about the same thing. I know Alexis Pardo Isla once said that the orchids we grow are selected for those that will grow in flasking medium. So that would be a basic difference between those we have in captivity and the wild type. K Barrett "J Fortuna" wrote in message ... This is not off topic even though the beginning may sound like it is, so please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
Kathy,
Actually I did not see the Nova program myself, just heard someone talk about it. Sometimes (like this one) I regret not having a TV antenna or cable. However, most of the time I think we've made a wise choice: I know if I had TV reception I would spend hours watching it, and then I couldn't spend all this time here on rgo, and read as many books as I do, etc. Joanna "K Barrett" wrote in message news:z6QUb.186773$sv6.989867@attbi_s52... That was a wonderful Nova program, wasn't it!! Made me start wondering about the same thing. I know Alexis Pardo Isla once said that the orchids we grow are selected for those that will grow in flasking medium. So that would be a basic difference between those we have in captivity and the wild type. K Barrett "J Fortuna" wrote in message ... This is not off topic even though the beginning may sound like it is, so please bear with me: I recently heard that when wolves are tamed, one of the side-effects of taming is that their fur turns a lighter color. I forget exactly what the explanation was, but I think it was something like the same chemical substance being responsible for anxiety/fear/wildness in character as well as darkness of fur. Leap in thinking from wolves to orchid plants ... This made me wonder about some of the effects that cultivation has on orchid species. I would guess that a cultivated orchid species might grow bigger and live longer than its wild counterpart of the same species, etc. That at least would seam logical to me, since the cultivated species are likely to be fertilized more regularly, and the environment is more likely to be adjusted to be closer to ideal conditions than might occur in nature, if the grower knows what they are doing. Also I know that plants within the species won't be exactly the same, and the orchid grower might decide to cross two orchids that are in the same species and share some trait that does not occur in all orchids of this species to try to promote this trait which might have gotten lost in the wild (where natural selection or chance might have caused this trait to not be propagated). Any other ideas? Either based on your experience, your knowledge, or your hypothesizing on this subject? I would be interested in finding out more. I wonder if there are any effects that cultivation has had on orchid species that are less obvious/logical (similar to the lightening of fur in wolves, which I would never have guessed if I had not learned about it). Are there any good examples of orchids where the same species in cultivation tends to be quite different in some significant way from its wild counterpart? Thanks, Joanna |
wild to cultivated changes?
This link, which asks the question, "Is it possible to identify individual
dogs as members of a specific breed?" is interesting with regard to the question of what is a species and what is a variety within a species. I was thinking of all the different varieties of Phal. equestris I have accumulated while I was reading it. http://www.eurowaf.org/id.htm I found it while I was searching for a bit of info I remembered about how much of the variation in dog breeds comes from mutations that occurred in a group of genes that switch on and off at different times during a puppy fetus's growth. I think this is a sub group within the hox box gene group While I was looking I also came across a link that better explained the idea of neoteny in dogs. For what it's worth, http://www.wolfology.com/id86.htm I newver did find the puppy fetus thing and I forget why i was looking for it... Anyway, I guess these links are somewhat helpful to people like me seeking to understand what is really going on in our genes... and the genes of our orchids (keep it topical)... and what you guys can talk so intelligently about. I remember reading someplace that the gene group which controls early embryonic development in all animal species are exactly the same no matter where they show up on a species chomosomes. From mice to men and from chickens to fruit flies and worms, this gene group works so well to get things started and causes things to go so terribly wrong if it mutates that it is invariable across the whole spectrum of animal life on this planet. When every animal on this planet gets started the same set of chemical switches is thrown in the exact same order because the same genes do it. I keep thinking this gene group is called the hox box, but that's wrong. The hox box is like the next main group of gene switches tha tcomes into play during early embryo development. Mutations to it are supposedly responsible for what makes each life-form group unique from all the others life-form groups in terms of body shape. "If this switch is not thrown at this exact moment in the sequence you don't develop legs, arms, wings or fins and you grow up to be a snake (or at least something without legs, arms, wings or fins)..." All life has certain basic things in common. What makes us different is not nearly as important as what makes us the same. As the Aliens say, "you won't be sorry if you try to prove yourself unique and apart because it will teach you what a great and important organism you are a part of....." (They're so full of crap. They recently rejected my latest attempt at "Hamlet Unaided" saying only "Your pencil is clearly not as sharp as you want us to think it is.") That was really interesting and coherent stuff, BTW. What you all wrote, I mean... I hope there's more... I won't interrupt again. And you know Rob: requarding the Alien's return to get me... It will be so nice when they do. If for no other reason then it means they must have left at some point.... Rob Halgren" wrote in message ... How identical *is* species DNA anyway? Is the genome like a template? If one could put the entire DNA strands of a species on an overhead projector acetate, could one overlay all the G-C and A-T base pairs on top of one another would they all line up? Could you say that any variation within that line-up would be something like 'different colored eyes, and so same species' or 'different all together and so a hybrid'? I mean, how can one isolate individual variation within a species? And how would one know that the aberrant base pairs weren't individual variation but the result of hybridization? This _is_ actually my field, for once... And yes, the genome is a template, if you aligned all of the DNA for all of the individuals in a species, it would line up pretty darn well. The last estimate I heard for the human genome was one SNP (single nucleotide polymorphism) for every 1000 bases or so. Not every SNP (in fact very few) actually does anything significant to a gene. We don't know enough now to read the genome quite like a book. The main problem is that there are very few single locus traits, most are multiple loci working in various degrees of collaboration. It isn't easy to read a book when the sentences bounce around between chapters and the grammar isn't entirely worked out. How do you know the difference between individual variation and hybridization? In a grossly oversimplified view: Most of the genes for two closely related species will be very close in sequence. This is as it should be, if they are derived from a common ancestor. But, if you look at the right genes, there should be a consistent difference in the sequence between two species. If you know that difference, then it is easy to look and see if an organism has two copies of organism A's gene, two copies of organism B's gene, or one of each. You need to look at many different genes, usually. Actually, a variation of this is exactly how a paternity test works (children are hybrids too). Note that is only the closely related things that we have a problem with... We can all tell that Paph. rothschildianum and Paph. armeniacum are distinct species. We can get a pretty good idea that Paph. Dollgoldii is a hybrid. We don't need DNA evidence for that... Who is to say what species DNA is? Lord knows there's enough bickering and infighting amongst taxonomists who classify species according to set international rules. Who would be the agency that would determine and stamp approve what 'species DNA' looks like? And how would they know? What if they missed a few individuals? Like if a Greater Alien Space Race came to the Earth they'd think by preponderance of numbers that the human species was Asian, and take that DNA as criteria of human-ness. The tiny Bushman from the Kalihari Desert would be shit out of luck because they don't look Asian. What then? Would The Aliens be justified in eating Bushmen because, according to their definition of human-ness, they weren't human? I actually have a talk about this worked up for orchids... The answer is that there is no magic answer when you use DNA, any more than there is when you use phenotypic markers for taxonomy. But, you can get good estimates of how far apart things are. The boundaries are always a mess, and always will be. DNA is just another tool. A powerful tool. Somebody still needs to decide just how far apart is far enough to qualify as a separate species. What makes something a distinct species is genetic isolation and time. Given enough of each, you don't fancy science to tell them apart. It is those fuzzy edges that kick you in the head. When Al's aliens come to pick him up, they will realize that his DNA is 99.9999%+ similar to both the Kalihari bushman and the Eskimo. It is extraordinarily similar to that of a chimpanzee. It is remarkably similar (in both sequence and the organization of the genes on the chromosomes) to the DNA of a mouse. It is somewhat (disturbingly) similar to the sequence and organization of the genes on the chromosome of the zebra fish. The farther apart we get, the more difference there is, but there is still remarkable conservation. Besides, we all know that the aliens (or monsters) eat the cute, mysteriously underdressed girls, who get separated from their group of friends by strange plot twists. I learned that from the movies. Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
"K Barrett" wrote in message news:h1WUb.108599$U%5.557761@attbi_s03... Thanks for your response. It'll take me a while to assimilate it (I know, its futile...) Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. Cheers, Ted |
wild to cultivated changes?
Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
When you are looking a gene map, you are looking at a template for
making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
When you are looking a gene map, you are looking at a template for
making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
Al wrote:
When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Effectively. Turns out that although chromosomes break and swap pieces all the time (with their partner chromosome, remember, orchids are nominally 2N - diploid), the breakage isn't random. Geneticists thought it was random for the longest time, but it turns out there are 'hotspots' which tend to recombine more frequently than the rest of the chromosome. So large pieces of DNA tends to move in 'chunks'. And yes, we have to assume (because it works, among other things), that function and sequence are inherited from common ancestors. These sequences change with time, but the function must be conserved if the gene is critical. If the gene isn't critical, it can diverge faster, but will still be related to its ancestral sequence. Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? Not as far as I know. I don't think we know enough about the genomes of enough plants. We did a project here which looked at genes which were 'specific to plants', but not flowering vs. non-flowering. This has holes you can drive a truck through, for various technical reasons, btw. If there is a group of 'flowering specific genes' I don't know about them. Doesn't mean they don't exist, and I'll be happy to take citations... How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Genes are found a) by similarity to known genes - we know a lot of genes, b) by software that looks at the genome and tries to predict gene structure - it is 'trained' on a reference set and let loose on your genome, or c) by good old fashioned cloning - a scientist generates a copy of a mRNA (the 'message RNA' that gets translated into a protein), and we work backwards from there. No, we can't tell between angiosperms and gymnosperms just by sequence. We could take a gene sequence from a bunch of different organisms and run software that tells us what is 'most closely related' (quotes mine) to what. It might divide them into those two classes, or not... Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I'd bet good money that flowering (as we think of it) is a single evolutionary event, with all of the flowering plants descended from a single common ancestor. I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I guess so... That is not a wrong way of thinking about it, anyway. I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? If we had enough information, probably. Somebody might be working on it as we speak. There are a lot of questions out there. Your questions are pretty good ones. I might steal a few for my own work, if you don't mind... *grin* Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
When you are looking a gene map, you are looking at a template for
making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
Al wrote:
When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Effectively. Turns out that although chromosomes break and swap pieces all the time (with their partner chromosome, remember, orchids are nominally 2N - diploid), the breakage isn't random. Geneticists thought it was random for the longest time, but it turns out there are 'hotspots' which tend to recombine more frequently than the rest of the chromosome. So large pieces of DNA tends to move in 'chunks'. And yes, we have to assume (because it works, among other things), that function and sequence are inherited from common ancestors. These sequences change with time, but the function must be conserved if the gene is critical. If the gene isn't critical, it can diverge faster, but will still be related to its ancestral sequence. Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? Not as far as I know. I don't think we know enough about the genomes of enough plants. We did a project here which looked at genes which were 'specific to plants', but not flowering vs. non-flowering. This has holes you can drive a truck through, for various technical reasons, btw. If there is a group of 'flowering specific genes' I don't know about them. Doesn't mean they don't exist, and I'll be happy to take citations... How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Genes are found a) by similarity to known genes - we know a lot of genes, b) by software that looks at the genome and tries to predict gene structure - it is 'trained' on a reference set and let loose on your genome, or c) by good old fashioned cloning - a scientist generates a copy of a mRNA (the 'message RNA' that gets translated into a protein), and we work backwards from there. No, we can't tell between angiosperms and gymnosperms just by sequence. We could take a gene sequence from a bunch of different organisms and run software that tells us what is 'most closely related' (quotes mine) to what. It might divide them into those two classes, or not... Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I'd bet good money that flowering (as we think of it) is a single evolutionary event, with all of the flowering plants descended from a single common ancestor. I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I guess so... That is not a wrong way of thinking about it, anyway. I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? If we had enough information, probably. Somebody might be working on it as we speak. There are a lot of questions out there. Your questions are pretty good ones. I might steal a few for my own work, if you don't mind... *grin* Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
When you are looking a gene map, you are looking at a template for
making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
Al wrote:
When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Effectively. Turns out that although chromosomes break and swap pieces all the time (with their partner chromosome, remember, orchids are nominally 2N - diploid), the breakage isn't random. Geneticists thought it was random for the longest time, but it turns out there are 'hotspots' which tend to recombine more frequently than the rest of the chromosome. So large pieces of DNA tends to move in 'chunks'. And yes, we have to assume (because it works, among other things), that function and sequence are inherited from common ancestors. These sequences change with time, but the function must be conserved if the gene is critical. If the gene isn't critical, it can diverge faster, but will still be related to its ancestral sequence. Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? Not as far as I know. I don't think we know enough about the genomes of enough plants. We did a project here which looked at genes which were 'specific to plants', but not flowering vs. non-flowering. This has holes you can drive a truck through, for various technical reasons, btw. If there is a group of 'flowering specific genes' I don't know about them. Doesn't mean they don't exist, and I'll be happy to take citations... How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Genes are found a) by similarity to known genes - we know a lot of genes, b) by software that looks at the genome and tries to predict gene structure - it is 'trained' on a reference set and let loose on your genome, or c) by good old fashioned cloning - a scientist generates a copy of a mRNA (the 'message RNA' that gets translated into a protein), and we work backwards from there. No, we can't tell between angiosperms and gymnosperms just by sequence. We could take a gene sequence from a bunch of different organisms and run software that tells us what is 'most closely related' (quotes mine) to what. It might divide them into those two classes, or not... Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I'd bet good money that flowering (as we think of it) is a single evolutionary event, with all of the flowering plants descended from a single common ancestor. I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I guess so... That is not a wrong way of thinking about it, anyway. I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? If we had enough information, probably. Somebody might be working on it as we speak. There are a lot of questions out there. Your questions are pretty good ones. I might steal a few for my own work, if you don't mind... *grin* Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
When you are looking a gene map, you are looking at a template for
making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
Al wrote:
When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Effectively. Turns out that although chromosomes break and swap pieces all the time (with their partner chromosome, remember, orchids are nominally 2N - diploid), the breakage isn't random. Geneticists thought it was random for the longest time, but it turns out there are 'hotspots' which tend to recombine more frequently than the rest of the chromosome. So large pieces of DNA tends to move in 'chunks'. And yes, we have to assume (because it works, among other things), that function and sequence are inherited from common ancestors. These sequences change with time, but the function must be conserved if the gene is critical. If the gene isn't critical, it can diverge faster, but will still be related to its ancestral sequence. Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? Not as far as I know. I don't think we know enough about the genomes of enough plants. We did a project here which looked at genes which were 'specific to plants', but not flowering vs. non-flowering. This has holes you can drive a truck through, for various technical reasons, btw. If there is a group of 'flowering specific genes' I don't know about them. Doesn't mean they don't exist, and I'll be happy to take citations... How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Genes are found a) by similarity to known genes - we know a lot of genes, b) by software that looks at the genome and tries to predict gene structure - it is 'trained' on a reference set and let loose on your genome, or c) by good old fashioned cloning - a scientist generates a copy of a mRNA (the 'message RNA' that gets translated into a protein), and we work backwards from there. No, we can't tell between angiosperms and gymnosperms just by sequence. We could take a gene sequence from a bunch of different organisms and run software that tells us what is 'most closely related' (quotes mine) to what. It might divide them into those two classes, or not... Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I'd bet good money that flowering (as we think of it) is a single evolutionary event, with all of the flowering plants descended from a single common ancestor. I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I guess so... That is not a wrong way of thinking about it, anyway. I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? If we had enough information, probably. Somebody might be working on it as we speak. There are a lot of questions out there. Your questions are pretty good ones. I might steal a few for my own work, if you don't mind... *grin* Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
Al wrote:
When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Effectively. Turns out that although chromosomes break and swap pieces all the time (with their partner chromosome, remember, orchids are nominally 2N - diploid), the breakage isn't random. Geneticists thought it was random for the longest time, but it turns out there are 'hotspots' which tend to recombine more frequently than the rest of the chromosome. So large pieces of DNA tends to move in 'chunks'. And yes, we have to assume (because it works, among other things), that function and sequence are inherited from common ancestors. These sequences change with time, but the function must be conserved if the gene is critical. If the gene isn't critical, it can diverge faster, but will still be related to its ancestral sequence. Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? Not as far as I know. I don't think we know enough about the genomes of enough plants. We did a project here which looked at genes which were 'specific to plants', but not flowering vs. non-flowering. This has holes you can drive a truck through, for various technical reasons, btw. If there is a group of 'flowering specific genes' I don't know about them. Doesn't mean they don't exist, and I'll be happy to take citations... How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Genes are found a) by similarity to known genes - we know a lot of genes, b) by software that looks at the genome and tries to predict gene structure - it is 'trained' on a reference set and let loose on your genome, or c) by good old fashioned cloning - a scientist generates a copy of a mRNA (the 'message RNA' that gets translated into a protein), and we work backwards from there. No, we can't tell between angiosperms and gymnosperms just by sequence. We could take a gene sequence from a bunch of different organisms and run software that tells us what is 'most closely related' (quotes mine) to what. It might divide them into those two classes, or not... Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I'd bet good money that flowering (as we think of it) is a single evolutionary event, with all of the flowering plants descended from a single common ancestor. I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I guess so... That is not a wrong way of thinking about it, anyway. I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? If we had enough information, probably. Somebody might be working on it as we speak. There are a lot of questions out there. Your questions are pretty good ones. I might steal a few for my own work, if you don't mind... *grin* Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
When you are looking a gene map, you are looking at a template for
making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
Al wrote:
When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Effectively. Turns out that although chromosomes break and swap pieces all the time (with their partner chromosome, remember, orchids are nominally 2N - diploid), the breakage isn't random. Geneticists thought it was random for the longest time, but it turns out there are 'hotspots' which tend to recombine more frequently than the rest of the chromosome. So large pieces of DNA tends to move in 'chunks'. And yes, we have to assume (because it works, among other things), that function and sequence are inherited from common ancestors. These sequences change with time, but the function must be conserved if the gene is critical. If the gene isn't critical, it can diverge faster, but will still be related to its ancestral sequence. Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? Not as far as I know. I don't think we know enough about the genomes of enough plants. We did a project here which looked at genes which were 'specific to plants', but not flowering vs. non-flowering. This has holes you can drive a truck through, for various technical reasons, btw. If there is a group of 'flowering specific genes' I don't know about them. Doesn't mean they don't exist, and I'll be happy to take citations... How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Genes are found a) by similarity to known genes - we know a lot of genes, b) by software that looks at the genome and tries to predict gene structure - it is 'trained' on a reference set and let loose on your genome, or c) by good old fashioned cloning - a scientist generates a copy of a mRNA (the 'message RNA' that gets translated into a protein), and we work backwards from there. No, we can't tell between angiosperms and gymnosperms just by sequence. We could take a gene sequence from a bunch of different organisms and run software that tells us what is 'most closely related' (quotes mine) to what. It might divide them into those two classes, or not... Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I'd bet good money that flowering (as we think of it) is a single evolutionary event, with all of the flowering plants descended from a single common ancestor. I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I guess so... That is not a wrong way of thinking about it, anyway. I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? If we had enough information, probably. Somebody might be working on it as we speak. There are a lot of questions out there. Your questions are pretty good ones. I might steal a few for my own work, if you don't mind... *grin* Rob -- Rob's Rules: http://www.msu.edu/~halgren 1) There is always room for one more orchid 2) There is always room for two more orchids 2a. See rule 1 3) When one has insufficient credit to purchase more orchids, obtain more credit |
wild to cultivated changes?
While I was working out in the greenhouse i may have answered one of my own
questions/assumptions: Because the gene group responsible for 'making flowers' is a gene group that has been in the 'gene pool' for millions of years and copied itself into may various organisms, it has moved around and changed alot. The various gene components have separated from each other, crossed onto different chromosomes, developed mutations, etc. So the group may still work to 'make flowers' in all the species that make flowers. However, comparing the templates of, say, an oak tree and a petunia even the discerning viewer would not recognize a common gene structure that was responsible for this task? The genes to 'make flowers' are still there but they don't look the same from template to template? I think one big mystery is that they continue to do the same thing even though they have changed so much. Is this right? Or is too simple? Still there has to be something to the idea that the gene group responsible for making flowers in all species that makes flowers has common features across the spectrum of species templates? I've got a headache. "Al" wrote in message om... When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
While I was working out in the greenhouse i may have answered one of my own
questions/assumptions: Because the gene group responsible for 'making flowers' is a gene group that has been in the 'gene pool' for millions of years and copied itself into may various organisms, it has moved around and changed alot. The various gene components have separated from each other, crossed onto different chromosomes, developed mutations, etc. So the group may still work to 'make flowers' in all the species that make flowers. However, comparing the templates of, say, an oak tree and a petunia even the discerning viewer would not recognize a common gene structure that was responsible for this task? The genes to 'make flowers' are still there but they don't look the same from template to template? I think one big mystery is that they continue to do the same thing even though they have changed so much. Is this right? Or is too simple? Still there has to be something to the idea that the gene group responsible for making flowers in all species that makes flowers has common features across the spectrum of species templates? I've got a headache. "Al" wrote in message om... When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
The January issue of Scientific American had an article about mRNA or other
genetic material and its influence on things like schzophrenia etc. i got the issue in audio format, so I can listen in the GH, however I find it difficult to concentrate on something so minute while orchiding. It will have to wait for a long car trip when I can listen in peace without engaging my mind... like while driving, *G* K Barrett (apropos of nothing) "Al" wrote in message ... While I was working out in the greenhouse i may have answered one of my own questions/assumptions: Because the gene group responsible for 'making flowers' is a gene group that has been in the 'gene pool' for millions of years and copied itself into may various organisms, it has moved around and changed alot. The various gene components have separated from each other, crossed onto different chromosomes, developed mutations, etc. So the group may still work to 'make flowers' in all the species that make flowers. However, comparing the templates of, say, an oak tree and a petunia even the discerning viewer would not recognize a common gene structure that was responsible for this task? The genes to 'make flowers' are still there but they don't look the same from template to template? I think one big mystery is that they continue to do the same thing even though they have changed so much. Is this right? Or is too simple? Still there has to be something to the idea that the gene group responsible for making flowers in all species that makes flowers has common features across the spectrum of species templates? I've got a headache. "Al" wrote in message om... When you are looking a gene map, you are looking at a template for making an individual that has been copied, (added to and slightly rearranged and altered) from every individual ancestor from which it has descended? So it seems that across species, genera and families of organisms, the groups of genes that do something which helps the individual pass those genes would have a common look and function across the broad spectrum of creatures they create? These are questions? :-) Have a group of genes been found in plants that are only found in plants which produce flowers? Have a group of genes been found in orchids that are not found in any other flowering plants? Wouldn't such a finding indicate that the gene group is responsible for something that happens in flowering plants but not in other plants, or in orchids but not in other flowering plants? How do they find genes? Is it possible (yet) for a trained botanist/geneticist to look at a bunch of genes and tell if it is a gymnosperm or an angiosperm? That identifying structure he/she is looking for being a thing common to all angiosperms but that is not present in gymnosperms? Did the flowering organ in plants develop in many different unrelated species of non-flowering plants, and therefore maybe be relatively uneasy to compare and identify in other flowering plant's genes? I am sure gene groups that do the same thing in different animals are moved all over the place in the various species they construct and may not even stay together on the same chromosome even if they perform the same function, so it follows that the relatedness of species and individuals has something to do with where known gene groups are located in the templates when compared to each other? I would guess that the genes of plants would travel through time and species the same way they travel through the genes of the animal kingdom. A group of genes that performs a specific function in any organism descended from a previous ancestor would be found in some form in all species that, like the hox box gene that determines the development of appendages in fetus. Can genes that 'make a flower' or "make a fused reproductive organ called a column" be located by comparing and contrasting genes from many species? I think there is a common question in all of these questions. There certainly seems to be a set of assumptions which I do not even know to be correct. I am genetically incapable of writing tight concise short sentences. The same gene responsible for this behavioral trait is what makes my... well, never mind... Al Rob Halgren wrote in message ... Take your time to assimilate. We'll still be here and happy to help. But please don't slander yourself again like that. It is NOT futile. Way back, many many years ago, when I was teaching, I would rebuke any student who made such a remark, encouraging them to have more confidence. You can learn and understand anything you wish, if you are honestly trying. If, in such a circumstance, you don't understand something I have said, the fault is mine; not yours. That is my philosophy too. Glad to see there are other people who actually care about teaching out there. If you didn't understand me, it was because I didn't use the right words. There are exceptions for people who just don't listen, but you can't teach them anything they don't already know anyway. Rob |
wild to cultivated changes?
Al, I hope the head ache is a little better and this does not make it much
worst. If this does, just remember I'm a farmer who is out of date (while writing this I am referring to a book coauthered by Watson) and has forgotten most of what I learned about this sort of stuff. That being said, I think you are thinking on much to simple of terms. I think it is a mistake to think in terms of flower templates just as I would not call a complex computer program a template. The making of a flower is more a process with genes being turned on and off at different times and the various proteins produced interacting with each other. A gene is a template for a protein. There is DNA transcription to RNA which is translated into a protein or an enzyme (which is itself a proteins). At the underclass level each gene is a template for a unique protein. If there is a protein that is in all flowers and only in flower tissue, we could find the gene associated with this protein and all flowering plants would have this gene in their DNA. Problem is a non flowering plant could also have this gene, but never turn it on. A flower is probably composed of 100's of proteins (50 to 1000 is a good guess, I do not know if counts have been made). To make a flower these proteins must be made at the right time, in the right mix, and at the right place. I do not think anyone really has a grasp on how this is all controlled, but I think people have played with gene precursors to affect the number of petals produced on a flower. When you are working in the lab with a piece of undifferentiated tissue, one hormone will cause it to grow into a plant while another will cause it to grow into a flower. I think this fits into this discussion, but I am not sure how or why. Pat B |
wild to cultivated changes?
Hi Joanna,
If you look at a plant's DNA only a small percent will actually be part of a gene and thus only a small percent is used in the coding for protein. If you look at a chromosome (a DNA strand) it looks something like: . . . "tr a s h" . precursor . gene . " t r a s h" . precursor . gene. . . . One of the things science has been doing is gene mapping, finding which chromosome and where on the chromosome a gene is located. But, the largest percent DNA material will fall into the trash category. About ten years ago (I am very out of date) I attended a seminar discussing this "trash" DNA. (If they can not explain it, it must be trash --ha) One theory was tied to evolution where some of the trash contained coding used by ancient ancestors and no longer used. The same theory speculated that coding that will be used in some future evolved generation is sitting in the trash waiting to be turned on. Thus if a flowering plant evolved into a non flowering plant, the non flowering plant could still carry the coding for a protein required in a flower. I do not think it is very likely some non flowering species is going to evolve into an orchid. In an evolutionary time scale, I expect new orchid species will result from current orchid species adapting to new niches and global changes. Pat "J Fortuna" wrote in message ... Pat, Thanks for this info. I have been following this thread closely, though I only understand some of it, but I wish I understood all!nna, One thought occurred to me after reading your statement: If there is a protein that is in all flowers and only in flower tissue, we could find the gene associated with this protein and all flowering plants would have this gene in their DNA. Problem is a non flowering plant could also have this gene, but never turn it on. So does this mean that there could be a plant somewhere out there that is currently a non-flowering, purely-leafy plant, but if a descendent of this plant turned on the flowering gene it might actually flower, and we might get a completely new orchid species? I think I read somewhere that orchids are mainly or only identifiable as orchids because of the flowers, and so I am thinking that there could be a plant species out there that would be an orchid if only it did flower but it never does. Does this make sense, or should I just go back to open-mouthed lurker status on the continuation of this fascinating thread? Thanks, Joanna "Pat Brennan" wrote in message ... Al, I hope the head ache is a little better and this does not make it much worst. If this does, just remember I'm a farmer who is out of date (while writing this I am referring to a book coauthered by Watson) and has forgotten most of what I learned about this sort of stuff. That being said, I think you are thinking on much to simple of terms. I think it is a mistake to think in terms of flower templates just as I would not call a complex computer program a template. The making of a flower is more a process with genes being turned on and off at different times and the various proteins produced interacting with each other. A gene is a template for a protein. There is DNA transcription to RNA which is translated into a protein or an enzyme (which is itself a proteins). At the underclass level each gene is a template for a unique protein. If there is a protein that is in all flowers and only in flower tissue, we could find the gene associated with this protein and all flowering plants would have this gene in their DNA. Problem is a non flowering plant could also have this gene, but never turn it on. A flower is probably composed of 100's of proteins (50 to 1000 is a good guess, I do not know if counts have been made). To make a flower these proteins must be made at the right time, in the right mix, and at the right place. I do not think anyone really has a grasp on how this is all controlled, but I think people have played with gene precursors to affect the number of petals produced on a flower. When you are working in the lab with a piece of undifferentiated tissue, one hormone will cause it to grow into a plant while another will cause it to grow into a flower. I think this fits into this discussion, but I am not sure how or why. Pat B |
wild to cultivated changes?
"Rob Halgren" wrote in message ... Pat Brennan wrote: Hi Joanna, If you look at a plant's DNA only a small percent will actually be part of a gene and thus only a small percent is used in the coding for protein. If you look at a chromosome (a DNA strand) it looks something like: . . . "tr a s h" . precursor . gene . " t r a s h" . precursor . gene. . . . Actually, in plants it looks more like this: "trash".precursor.part1ofgene.junk.part2ofgene.jun k.part3ofgene.junk". There is a whole lot of nothin' that breaks up the actual coding parts of a lot of genes. Those are called introns, and I don't know that anybody knows what they are for, either. Bacteria don't have them and they get along just fine. It has been more than ten years since I last discussed this with a specialist in the genetics of animal development. At that time at least, it was believed that the suite of introns used to form a gene varies through development, so, for example, the actual composition of your hemoglobin right now is different from what it was when you were a kid, and will be different again when you're an ol' fossil like me. So, according to what she told me, what counts as an intron or exon (what some refer to as junk) will depend on age as well as the gene in question. Alas, she didn't have answers for many of my questions, like "How exactly does the selection of introns vs exons happen?" or "How is the gene constructed from the introns once the introns have been made?" or "Is there any intermingling of introns from different genes (e.g. is it possible to have an intron from one gene in between the introns of some other gene); if so, how does the cell know which introns are part of a given gene? or "How is the correct sequence of introns in the gene stored and later recovered for use?" or "Does all this happen in the nucleus?" or "How does the mechanism in a given nucleus know what the age of the organism is in order to know which introns to use at any given time?" or "Do the proteins within a chromosome have a role in any of this, and if so, what?" Do you know if any progress has been made in addressing any of these questions? Cheers, Ted |
wild to cultivated changes?
"Rob Halgren" wrote in message ... Pat Brennan wrote: Hi Joanna, If you look at a plant's DNA only a small percent will actually be part of a gene and thus only a small percent is used in the coding for protein. If you look at a chromosome (a DNA strand) it looks something like: . . . "tr a s h" . precursor . gene . " t r a s h" . precursor . gene. . . . Actually, in plants it looks more like this: "trash".precursor.part1ofgene.junk.part2ofgene.jun k.part3ofgene.junk". There is a whole lot of nothin' that breaks up the actual coding parts of a lot of genes. Those are called introns, and I don't know that anybody knows what they are for, either. Bacteria don't have them and they get along just fine. It has been more than ten years since I last discussed this with a specialist in the genetics of animal development. At that time at least, it was believed that the suite of introns used to form a gene varies through development, so, for example, the actual composition of your hemoglobin right now is different from what it was when you were a kid, and will be different again when you're an ol' fossil like me. So, according to what she told me, what counts as an intron or exon (what some refer to as junk) will depend on age as well as the gene in question. Alas, she didn't have answers for many of my questions, like "How exactly does the selection of introns vs exons happen?" or "How is the gene constructed from the introns once the introns have been made?" or "Is there any intermingling of introns from different genes (e.g. is it possible to have an intron from one gene in between the introns of some other gene); if so, how does the cell know which introns are part of a given gene? or "How is the correct sequence of introns in the gene stored and later recovered for use?" or "Does all this happen in the nucleus?" or "How does the mechanism in a given nucleus know what the age of the organism is in order to know which introns to use at any given time?" or "Do the proteins within a chromosome have a role in any of this, and if so, what?" Do you know if any progress has been made in addressing any of these questions? Cheers, Ted |
wild to cultivated changes?
"Rob Halgren" wrote in message ... Pat Brennan wrote: Hi Joanna, If you look at a plant's DNA only a small percent will actually be part of a gene and thus only a small percent is used in the coding for protein. If you look at a chromosome (a DNA strand) it looks something like: . . . "tr a s h" . precursor . gene . " t r a s h" . precursor . gene. . . . Actually, in plants it looks more like this: "trash".precursor.part1ofgene.junk.part2ofgene.jun k.part3ofgene.junk". There is a whole lot of nothin' that breaks up the actual coding parts of a lot of genes. Those are called introns, and I don't know that anybody knows what they are for, either. Bacteria don't have them and they get along just fine. It has been more than ten years since I last discussed this with a specialist in the genetics of animal development. At that time at least, it was believed that the suite of introns used to form a gene varies through development, so, for example, the actual composition of your hemoglobin right now is different from what it was when you were a kid, and will be different again when you're an ol' fossil like me. So, according to what she told me, what counts as an intron or exon (what some refer to as junk) will depend on age as well as the gene in question. Alas, she didn't have answers for many of my questions, like "How exactly does the selection of introns vs exons happen?" or "How is the gene constructed from the introns once the introns have been made?" or "Is there any intermingling of introns from different genes (e.g. is it possible to have an intron from one gene in between the introns of some other gene); if so, how does the cell know which introns are part of a given gene? or "How is the correct sequence of introns in the gene stored and later recovered for use?" or "Does all this happen in the nucleus?" or "How does the mechanism in a given nucleus know what the age of the organism is in order to know which introns to use at any given time?" or "Do the proteins within a chromosome have a role in any of this, and if so, what?" Do you know if any progress has been made in addressing any of these questions? Cheers, Ted |
wild to cultivated changes?
"Rob Halgren" wrote in message ... Pat Brennan wrote: Hi Joanna, If you look at a plant's DNA only a small percent will actually be part of a gene and thus only a small percent is used in the coding for protein. If you look at a chromosome (a DNA strand) it looks something like: . . . "tr a s h" . precursor . gene . " t r a s h" . precursor . gene. . . . Actually, in plants it looks more like this: "trash".precursor.part1ofgene.junk.part2ofgene.jun k.part3ofgene.junk". There is a whole lot of nothin' that breaks up the actual coding parts of a lot of genes. Those are called introns, and I don't know that anybody knows what they are for, either. Bacteria don't have them and they get along just fine. It has been more than ten years since I last discussed this with a specialist in the genetics of animal development. At that time at least, it was believed that the suite of introns used to form a gene varies through development, so, for example, the actual composition of your hemoglobin right now is different from what it was when you were a kid, and will be different again when you're an ol' fossil like me. So, according to what she told me, what counts as an intron or exon (what some refer to as junk) will depend on age as well as the gene in question. Alas, she didn't have answers for many of my questions, like "How exactly does the selection of introns vs exons happen?" or "How is the gene constructed from the introns once the introns have been made?" or "Is there any intermingling of introns from different genes (e.g. is it possible to have an intron from one gene in between the introns of some other gene); if so, how does the cell know which introns are part of a given gene? or "How is the correct sequence of introns in the gene stored and later recovered for use?" or "Does all this happen in the nucleus?" or "How does the mechanism in a given nucleus know what the age of the organism is in order to know which introns to use at any given time?" or "Do the proteins within a chromosome have a role in any of this, and if so, what?" Do you know if any progress has been made in addressing any of these questions? Cheers, Ted |
wild to cultivated changes?
"Rob Halgren" wrote in message ... Pat Brennan wrote: Hi Joanna, If you look at a plant's DNA only a small percent will actually be part of a gene and thus only a small percent is used in the coding for protein. If you look at a chromosome (a DNA strand) it looks something like: . . . "tr a s h" . precursor . gene . " t r a s h" . precursor . gene. . . . Actually, in plants it looks more like this: "trash".precursor.part1ofgene.junk.part2ofgene.jun k.part3ofgene.junk". There is a whole lot of nothin' that breaks up the actual coding parts of a lot of genes. Those are called introns, and I don't know that anybody knows what they are for, either. Bacteria don't have them and they get along just fine. It has been more than ten years since I last discussed this with a specialist in the genetics of animal development. At that time at least, it was believed that the suite of introns used to form a gene varies through development, so, for example, the actual composition of your hemoglobin right now is different from what it was when you were a kid, and will be different again when you're an ol' fossil like me. So, according to what she told me, what counts as an intron or exon (what some refer to as junk) will depend on age as well as the gene in question. Alas, she didn't have answers for many of my questions, like "How exactly does the selection of introns vs exons happen?" or "How is the gene constructed from the introns once the introns have been made?" or "Is there any intermingling of introns from different genes (e.g. is it possible to have an intron from one gene in between the introns of some other gene); if so, how does the cell know which introns are part of a given gene? or "How is the correct sequence of introns in the gene stored and later recovered for use?" or "Does all this happen in the nucleus?" or "How does the mechanism in a given nucleus know what the age of the organism is in order to know which introns to use at any given time?" or "Do the proteins within a chromosome have a role in any of this, and if so, what?" Do you know if any progress has been made in addressing any of these questions? Cheers, Ted |
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