Craig writes:

>A good point.  If a 'large' mutation is possible then, if it were
>successful, it would spread through a population until at some point a
>significant proportion of the population had the characteristic.  The
>distribution of some measure of the characteristic would then be
>bimodal.  I do not know of any examples in nature of the type of
>distribution I am talking of (ok, I haven't looked), so perhaps large
>changes/jumps in evolution are not possible as the neodarwinists state
>or assume???

Do you mean "large" mutations such as a human born with seven
fingers on each
hand, a snake with two heads or an insect with legs growing out of its head
where its antennae should be? These are common mutations, and they are all
regulatory failures.

Don't think of the genome as being a flat space. It is as hierarchically
organized as any other form of engineered control structure, organized with
some high-level supervisory control mechanisms in place. Like any good
supervisor, the highest-level code in the genome does no work itself. It merely
carries around a clipboard and a pencil and points at what should be done. But
it doesn't always get it right -- and failures at this level generally cause
significant alterations in the developmental architecture of the phenotype.

When these macroscale mutations actually provide evolutionary advantage, they
persist in the germline of the population as "polymorphisms," and such
polymorphisms are quite common in insects. Here's a bit of recent text
regarding the polymorphisms that exist in green pea aphids:

"Discrete variation in wing morphology is a very common phenomenon in insects
and has been used extensively in the past 50 years as a model to study the
ecology and evolution of dispersal and life history traits (Harrison, 1980;
Roff, 1986; Zera and Denno, 1997). One of the alternative morphs is winged,
displays migratory tendency and has low fecundity, whereas the other morph is
short winged or wingless, sedentary and highly fecund. Wing morph determination
can be purely genetic, purely environmental, or some combination of the two
(Roff and Fairbairn, 1991; Zera and Denno, 1997)."

--http://www.nature.com/cgi-taf/DynaPage.taf?file=/hdy/journal/v89/n5/full
/6800146a.html

If you search the literature -- or even on Google -- you'll readily find a
thousand other examples.

Wirt Atmar
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