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About ten years ago (I am very out of date) I attended a seminar discussing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