Strange hybrids

MccarrickAD@nswccd.navy.mil
Tue, 29 Jun 1999 13:23:43 -0400

In the current issue of Technology Review (MIT), there is an article on both
sides of the discussion on bio-engineered plant crops. In that article the
author mentions the danger of back-hybridization of transgenic crops with
wild plants. The danger of these back-crosses is that the wild plants may
pick up the novel trait of the crop plant (insect resistance due to
internally produced chemical defenses, insecticide/herbicide resistance due
to internally produced enzymes, etc.).

Usually it is assumed that the only wild plants that are likely to cross
only with close relatives. The article sites that of 30 agriculturally
important plants, 25 were found to break the species barrier. Specifically
there was a rare cross between wheat and goatgrass. The amazing point is
that wheat carries 42 chromosomes, while goatgrass only 28 ! Indeed there
is a low rate of viability of the hybrid seeds, but not zero !

I see two issues to discuss; (1) the ethical issues involved in transgenic
research and field testing, and
(2) the impact on evolution/creation thought.

Regarding issue (2) I recall that Darwin seemed to lean on hybridization as
a most important method by which to generate the variations that natural
selection acted on. The more modern thought usually relies on gradual
accumulation of small (or medium/large - Punc Eq) mutations. Perhaps
naturally occurring hybridization is an important mechanism. Creationists
(YEC or PC) rely strongly on the species (or genus) barrier to distinguish
"micro" and "macro" evolution. This kind of cross makes the
Neanderthal/Sapiens cross look small.

Al McCarrick