Re: the most impressive example of mutation/natural selection (was FW: Just for Bertvan)

Stephen E. Jones (
Sat, 09 Oct 1999 21:08:43 +0800


On Tue, 5 Oct 1999 14:37:59 -0400, Behnke, James wrote:


MG>I'll discuss it. First, what is the most impressive example of
>mutation/natural selection that has been observed to happen?

JB>The most impressive study of the change of one species to another I have
>seen is the teosinte to corn transition being mediated by a mutation in one
>gene, studied by John Doebley.


This is however an example of mutation plus *artificial* selection,
*not* of "mutation/natural selection".

The most "the most impressive example of mutation/natural selection"
between teosinte and corn is in fact the *teosinte* which survives in
the wild as the `fitter' of the two variants.

The corn variant is in fact a "hopeful monster" unviable in the wild but
preserved by man for *his* (not the corn's) purposes, as Gould points

"Third, whom shall the hopeful monster choose as mate? It is only an
individual, however well endowed, and evolution
requires the spreading of favorable traits through populations. The
offspring of two such different forms as a normal individual and a hopeful
monster will probably be sterile or at least, in their peculiarly hybrid state,
no match for normals in natural selection. But Iltis's theory avoids this
problem by calling upon human aid to propagate the seeds. The
catastrophically transmutated teosinte plant is still a viable creature, with a
male tassel on its central spike and female ears in terminal positions on its
lateral branches.

Finally, one last interesting and unusual feature of Iltis's theory: it invokes
human feedback, not only to improve the initial ear by conventional
selection but also to make it a viable structure in the first place-a striking
example of interaction between two disparate species in nature. The corn
ear, as a natural object, may well be unworkable-for the husks, which
firmly enclose the cob as a result of shortening the lateral branch so
drastically, prevent any dispersal of seeds (kernels). In a state of nature, the
ear would simply rot where it fell or would seed new plants so close to
each other that no offspring would reach full maturity. But farmers can peel
off the husks and plant the seeds-converting a hopeless to a most hopeful
and useful monster.

Corn is the world's third largest crop, not far behind wheat and rice. As the
original staple of New World peoples, it built the civilizations of an entire
hemisphere. Today we grow 270 million acres of corn a year, producing
nearly 9 billion bushels. Most of it does not end up in tacos or corn chips,
but as animal feed-the primary source for our carnivorous appetites. We
need corn for a comfortable life, but corn needs us as well, simply to

(Gould S.J., "A Short Way to Corn", in "The Flamingo's Smile: Reflections
in Natural History", [1985], Penguin: London, 1991 reprint, pp372-373)


"The code of conduct that the naturalist wishing to understand the problem
of evolution must adopt is to adhere to facts and sweep away all a priori
ideas and dogmas. Facts must come first and theories must follow. The
only verdict that matters is the one pronounced by the court as proved
facts. Indeed, the best studies on evolution have been carried out by
biologists who are not blinded by doctrines and who observe facts coldly
without considering whether they agree or disagree with their theories."
(Grasse P.-P., "Evolution of Living Organisms: Evidence for a New
Theory of Transformation", Academic Press: New York NY, 1977, p8)