RE: Are developmental biologists irreducibly dense?

Tim Ikeda (tikeda@sprintmail.hormel.com)
Mon, 07 Jun 1999 22:24:59 -0400

Hello David.

[much snipped...]

I wrote:
>> Another factor is the basic tendency
>> of scientists to use reductionist approaches in their work.
>> That's just science - Things work *a lot* easier if you can
>> achieve "a reduction" in explanation. So, even though problems
>> may not be easily reducible to simpler ones, such an approach
>> will still be attempted and will always garner the most
>> interest when successful (read: publications). "Unreduced" problems
>> don't get much press -- After all, how much is there to say about
>> a problem you can't crack?

David replied:
> This is a less appealing reason. Those who do not think the genome
> plays the architects role are no less committed to finding causal
> explanations of phenomena.

True, but they are far less likely to publish in that field because
they are far less able to generate publishable results. That isn't
to say that advances in such areas are unimportant, only that any
advances are extremely difficult. Too many undefined parameters
are involved. Papers that report, "I can't get anywhere on this
problem because I can't get a handle on all the variables" do not
often make it through the review process.

Now, one way to get at some of those variables is to do all of
that nasty, reductionistic stuff which scientists are so good
at. We can't really take whacks at the big-ticket problems
until lot of the groundwork gets finished. I picture the
whole effort as a kind of boot-strapping process: some advances
in genetics provide a foundation for developmental research,
which in turn provides the context for further advances in
understanding the genetics...

[snipped...]
> I am genuinely surprised - pleasantly so! I requote two lines
> from Harold:
>>> "Most microbiologists look to the genome to play the architects
>>> role. From where we now stand, this seems to me a rejection of
>>> reason.
>You responded:
>> I like that reference except for the "rejection of reason" part
>> in the second paragraph. I think he's stretching things a bit.
>
>I would have expected you to dissent from the "Most microbiologists"
>part as well. Is this the case - or has the change occurred since
>Harold wrote?

You're right, I do dissent from the "most microbiologists" part
too. The "master regulator" or "master architect" -- if any one
part of the cell could be assigned that role -- has never been
identified.

> I am persisting with this thought because only a year
>later, a significant paper appeared in Developmental Biology which
>set out "an alternative to the solely genetic model of evolution
>and development". At that time, the authors were advancing something
>new! Here is an extended quote:
>
>"Just as the cell is seen to be the unit of structure and function
>in the body - not the genes that act through it - so the morpho-
>genetic field can be seen as a major unit of ontogenetic and phylo-
>genetic change. In declaring the morphogenetic field to be a major
>module of developmental and evolutionary change, we are, of course,
>setting it up as an alternative to the solely genetic model of
>evolution and development. This, however, is not to be seen as
>antagonistic to the principle that genes are important in evolution
>or development. This is not in any way denied. But just as the genes
>make the cells and the cells form the body, so the gene products
>first need to interact to create morphogenetic fields in order to
>have their effects. Changes in these fields then change the ways
>that animals develop."
>(page 368).
>Gilbert, S.F., Opitz, J.M. and Raff, R.A. 1996, Developmental
>Biology, 173, 357-372.

Masters of the obvious, IMHO. In every "new" branch of biology
you find a lot of people who think they invented the wheel.

The genome is often likened to a recipe or blueprint - A passive
role. But the genome turns out to also be "active" and changeable
as well. However, it is not the only object in the cell that
"calls the shots" and determines where everything else is supposed
to go. Each genome exists in a particular environment with a
particular history, and is influenced by that environment and
history. I, and most others (IMO), do not feel that genome sequences
can be completely understood outside of their environmental contexts.
I think I've heard the phrase, "the ecology of the gene" mentioned
to describe this. All this is uncontroversial.

As far as I can see, most of the catfights are about how far one
can get by making simplifying assumptions about the "genetic
environments" and the extent to which sequences influence
outcomes.

[...]
> Is there a UK vs US divide here? In the UK, vocal people are
> Dawkins, Maynard Smith and earlier James Watson. Brian Goodwin has
> tended to be a lone voice. Yet in the States you have a greater
> diversity of opinion on these matters.

Beats me. I tend to group scientific ideas by labs or lab pedigrees,
not by national or geographic criteria. Except for the French...

>I had written (to your aside):
>>> Yes. I do find it interesting that there are great divergencies
>>> of thinking between people who nominally have the same belief
>>> system. We see it in Christian circles and we see it in Marxist
>>> circles.
>You replied:
>> That's because we are genetically programmed to compete. It's
>> a direct consequence of Darwinian evolution ;*)

> Aha - the ultimate explanation! Darwinian storytelling at its
> best!

Science is _all_ storytelling. As are any other methods to
understand how and why things happen.

> (I think it is more to do with the American temperament, myself,
> with longings for the wild west and shoot-outs!)

Ah, you must be thinking of Detroit or the California freeways.

Regards,
Tim Ikeda
tikeda@sprintmail.hormel.com
(despam address before use)