Rapid shift in natural selection reported

U.S. evolutionary scientists say they have found evolution as a process can occur during eons or within months as a population's needs change.

In a study of island lizards exposed to a new predator, evolutionary biology and organismic Professor Jonathan Losos and colleagues at Harvard University found natural selection dramatically changed direction during a very short time -- within a single generation -- favoring first longer and then shorter hind legs.

"Because of its epochal scope, evolutionary biology is often caricatured as incompatible with controlled experimentation," said Losos, who did much of the work before joining Harvard this year from Washington University in St. Louis.

"Recent work has shown, however, that evolutionary biology can be studied on short time scales and that predictions about it can be tested experimentally," said Losos, who is also curator in herpetology at the Harvard Museum of Comparative Zoology. "We predicted, and then demonstrated, a reversal in the direction of natural selection acting on limb length in a population of lizards."

The research by Losos, Thomas Schoener and David Spiller of the University of California-Davis, and graduate study R. Brian Langerhans appears in the journal Science.

Copyright 2006 by United Press International