Helpful Mutations Didn’t Sweep Through Early Humans | Wired Science | Wired.com

Helpful Mutations Didn’t Sweep Through Early Humans | Wired Science | Wired.com: "Humans probably didn’t get swept up in evolution.

Scientists have favored a model of evolution in which beneficial gene mutations quickly and dramatically sweep through a population due to the evolutionary advantages they confer. Such mutations would become nearly universal in a population. But this selective sweep model may not be accurate for humans, a new study indicates. Human evolution likely followed a more subtle and complicated path, say population geneticists Molly Przeworski of the University of Chicago and Guy Sella of Hebrew University of Jerusalem and colleagues.

Computational analysis of 179 genomes belonging to people from Europe, Asia and Africa reveal that selective sweeps have been rare in human evolution, the researchers report in the Feb. 18 Science.

“I’m convinced,” says Andrew Clark, a population geneticist at Cornell University. Clark was among the first to find evidence that selective sweeps can shape evolution. The idea of a favored gene sweeping in to save the evolutionary day is so attractive that other forms of natural selection have been largely ignored, he says. The new study could change that. “I think this will be taken to heart and people will take a step back and start asking what other signatures of selection may be present.”"