On Thu, 15 May 2003 12:46:41 +0100, Stephen Howard
wrote:

On Thu, 15 May 2003 13:01:55 +0200, Tim
wrote:

On Thu, 15 May 2003 11:12:40 +0100, Stephen Howard
wrote:

On Thu, 15 May 2003 10:56:30 +0200, Tim
wrote:

The difference being that "pick-n-mix" cross breeding transfers any
number of unknown genes, whereas a GM organism would have only a very
few, well known, genes transfered.
The difference between the sledge-hammer and scalpel approaches. Which
one is best ?

You see...there it is again... 'any number of unknown genes'.
Precisely my point. If there are 'unknown genes' then there are
unknown properties.

I don't quite see what you're aguing about here. Plant breeders do this
all the time.

Yes, they do - and if it works it works because it's a natural process
- it's bringing nature to nature, and all that that encompasses.
What?

In other words, nature sorts it out in its own inimitable fashion.
Ah, but it's not inimitable, is it ? That's what GE is. Imitating.


Ever tried crossing a Leek with a Honeysuckle? Had any success?
Most likely not, because somewhere down the line evolution said
'uh-huh, no can do'.
That's a very simplistic view of evolution, isn't it?
You and I know there's more to it than that.

Simplistic it may be, but it is wrong?
In as much as saying "the bee wanted to suck nectar so eveolved a longer
proboscis" is wrong. Certainly misleading.



It's interesting that you regard the incredible intricacies of natural
selection as being akin to a 'sledgehammer approach'.

I didn't express myself very well there, sorry. The sledgehammer
approach was meant to be applied to artificial breeding, which to a
great degree side-steps natural selection, and replaces it with human,
artificial selection.

I quite agree there - but in that case we act as mere matchmakers.
You can bring together two people who might not normally meet, but
that doesn't mean they'll get on with each other. And if they do get
on, perhaps it will be in unexpected ways.

Going on from your matchmaking analogy, I'd see it as rather like getting a
shirt or tie that you saw someone else wearing, and looks good, and get
"your" person to put it on. Only one item, so you can see if it looks good
on them. Sometimes it will, sometimes it won't.

The point here is that there's a lot of interplay that goes on behind
the scenes that I'm not convinced we fully understand as yet.
True. I don't think many would disagree there.


In reality I'd say it's more like two buckets of sand being mixed up.
So, what would be less likely to produce any great unexpected changes -
mixing 2 buckets of sand, or just swapping a couple of grains over?

But sand is inert - it won't evolve, mutate or otherwise change its
properties. It's a poor analogy for a gene.

All analogies are poor. But do you see what I was trying to say ?


Natural selection can only work on variety. This variety is created by
mixing and remixing the available genes. A little ramdom input from
occasional mutations adds some novel variation as well, but it's a small
part. Mix everything up and see what survives. A simplification,
perhaps, but that's the backbone of the theory of natural selection.

Yes, I understand that - and by the same token that doesn't preclude a
mutation from wreaking havoc - but on the whole the system appears to
function very well indeed.
Of course. Otherwise we wouldn't be here.


I rather feel that nature's methods make your scalpel look like a blunt
sword.
It's not MY scalpel. If you just fuse germ cells, as happend in the
development of modern wheat strains for exaple, who knows what you're
making? Reduce the number of changes being made, and you have more
chance of finding any problems.

It's that element of 'chance' that's the problem, you see.
It's just not good enough to say 'hey, we can dabble with this and
tweak that.... and hope to hell we catch any adverse effects'.

Well, it's not just hoping, they should be looking pretty hard.

And just when d'you stop looking?

That's exactly the sort of question that has to be answered. And I don't
have an answer. But can only be answered by careful testing and discussion,
not by joining either of the entrenched camps and slinging mud and
accusations at each other, which seems to be happening more and more often.
So far we've managed to not insult each other after so much writing. Is
this a record for newsgroups?



Nature builds on balance - this is why folks who consistently use
pesticides get locked into using them, they create their own
imbalances.

I can't agree with you more. Bit hardly relevant to the topic is it?

The balance of nature isn't relevant to transgenic plants??
I don't think it is directly relevant to our discussion at the moment.
Generally yes. But, with teh right approach and development, maybe GM
plants could provide a way of gently easing them out of thier deadlocked
pesitcide use in the future. Which would surely be a good thing.


Nature doesn't stop working simply because mankind pitches
in with a few crude attempts at tipping the scales - if you leave a
hole, nature will fill it... and not necessarily to your advantage.

Without those unknown genes, how many holes will you create, and what
will fill them?
But we're not talking about building organisms from scratch, where there
would be huge great holes all over the genome. We're talking about
taking a whole genome and adding/changing just one or two genes.

So you have smaller holes, is all. And small holes have an annoying
habit of becoming large holes.

....some heal up.
Using a material analogy. No, you'd have little patches of different a
colour rather than holes.

And as you well know, the gene stands at the tip of the inverted
pyramid and interacts all the way up and through the plant's whole
structure...

CAN do, depending on the gene and where it is. Most genes are only active
for short periods and only in certain tissues. Which is why you don't get
red, scented roots on a red, scented rose bush. Those genes are only
activated in the relevant part(s) and the relevant time(s).

which then interacts with other organisms in the same
fashion... and so on ad infinitum. I'm not convinced that anyone is
fully aware of just what the knock-on effects might be.

No one is saying they are, except maybe the multi-nationals, but no-one
believes them anyway (at least I hope not).

Tim.