The research was led by Joe Thornton, assistant professor of biology at the University of Oregons Center for Ecology and Evolutionary Biology, and will be published in the April 7 issue of SCIENCE.

How natural selection can drive the evolution of tightly integrated molecular systems those in which the function of each part depends on its interactions with the other partshas been an unsolved issue in evolutionary biology. Advocates of Intelligent Design argue that such systems are "irreducibly complex" and thus incompatible with gradual evolution by natural selection.

"Our work demonstrates a fundamental error in the current challenges to Darwinism," said Thornton. "New techniques allow us to see how ancient genes and their functions evolved hundreds of millions of years ago. We found that complexity evolved piecemeal through a process of Molecular Exploitation -- old genes, constrained by selection for entirely different functions, have been recruited by evolution to participate in new interactions and new functions."

Thornton and coworkers used state-of-the-art statistical and molecular methods to unravel the evolution of an elegant example of molecular complexity the specific partnership of the hormone aldosterone, which regulates behavior and kidney function, along with the receptor protein that allows the bodys cells to respond to the hormone. They resurrected the ancestral receptor gene which existed more than 450 million years ago, before the first animals with bones appeared on Earth and characterized its molecular functions. The experiments showed that the receptor had the capacity to respond to aldosterone long before the hormone actually evolved.

Thorntons group then showed that the ancestral receptor a
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Contact: Mary Stanik
mstanik@uoregon.edu
541-346-3873
University of Oregon
6-Apr-2006