We keep having off and on discussions or observations about the phenotypic plasticity of Cyprinodon pupfishes, especially that of C. diabolis, the Devil's Hole pupfish. I just found a whole new literature, and one good review article, on the subject. The new issue of American Scientist, published by the Sigma Xi scientific honors society, has an article entitled, "The Phenotypic Plasticity of Death Valley's Pupfish", pp. 28-36, Vol. 96, No. 1, 2008, by Sean Lema. Lema and co-workers have done a series of tests and observations mostly with C. nevadensis sub-species (probably better thought of as populations, but that's my own humble opinion). What they found, in short, was that seemingly minor differences in temperature, dissolved oxygen, and food availability affected the rate of growth which in turn affects the final adult phenotype. The refugia-raised populations turn out to be bigger than wild-type Devil's Hole pupfish because they grow better and faster in the available environment. Another factor affecting rate of growth can be thyroid suppression, which results in a smaller fish. Their work has also extensively involved researching the effects of the hypothalamic neuropeptide arginine vasotocin (AVT), a key signal hormone in aggression and reproductive behaviors in males, especially. It's a really good review piece, with references to work in the scientific literature.

So both Martin and I were right, I suppose, in that this plasticity is not really the result of changing allele frequencies, but rather a genomic response to environmental variables. Cool stuff.

Vindication! I love it!!

For those who can't get enough on phenotype plasticity, I found an interesting review article by Sonia Sultan of Wesley University in the November issue of TREE (Trends in Ecology & Evolution). I didn't realize that a new term has been coined for this kind of research, "eco-devo" as opposed to the better known evo-devo. The crux is understanding how environmental cues are transduced into differential genetic expression (good work if you can get it!). Anyway, here's the article in .pdf form:

 EcoDevoInContextTREE.pdf   576.47KB   51 downloads