Does Mountain Living Slow Rate Of Molecular ...( A study of hummingbirds living high i...)

A study of hummingbirds living high in the Andes Mountains suggests that life at the top slows the pace of genetic evolution.

Findings from the study, which compares the DNA of 26 hummingbird species, is some of the first evidence to link an animal's physical environment to the rate at which genes evolve, something traditionally attributed mostly to the size, mass or other feature of the animal itself.

"This adds elevation to the mix of factors that one might consider as contributors to rates of molecular evolution," says Robert Bleiweiss, professor of zoology and the author of the recent study published in the Proceedings of the National Academy of Sciences.

In all animals, change is governed at the molecular level as genes change or mutate. Over long periods of time and many generations, these genetic changes accumulate and can manifest themselves in altered body plans or behaviors. But what initially sparks those changes at the genetic level is largely unknown.

The evidence that life at higher elevations slows the "molecular clock," says Bleiweiss, was a surprise since "the more extensive subdivision and speciation of bird
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Contact: Robert Bleiweiss
reb@ravel.zoology.wisc.edu
608-265-6027
University of Wisconsin-Madison
28-May-1998