May 20, 2009

Small evolutionary shifts make big impacts -- like developing night vision, researchers find

By Krishna Ramanujan

In the developing fetus, cell growth follows a very specific schedule. In the eye's retina, for example, cones -- which help distinguish color during the day -- develop before the more light-sensitive rods -- which are needed for night vision.

But minor differences in the timing of cell proliferation can explain the large differences found in the eyes of two species -- owl monkeys and capuchin monkeys -- that evolved from a common ancestor.

Researchers from Cornell, St. Jude's Children's Research Hospital in Tennessee and the Federal University of Para, Brazil, have found an evolutionary mechanism that provides insight into how important changes in brain structure of primates can evolve.

That evolution appears to proceed via simple genetic changes that affect the timing of development of brain regions, they report in a paper published May 18 online and in a future print issue of Proceedings of the National Academy of Sciences.

Full article here:

http://www.news.cornell.edu/stories/May09/primateEye.kr.html