Speeding Up the Evolution Debate

Article excerpt

university of Chicago researchers want to add a caveat to the prime Darwinian directive: Evolution is not just survival of the fittest, but of the fastest as well.

To evolve from point A to point B, Charles Darwin theorized, nature "selected" certain highly adaptive genetic mutations for species propagation.

But according to genetics researchers Bruce Lahn, Gerald Wyckoff, Christine Malcom, and Eric Vallender, natural selection is not the sole guarantor of survival. The speed at which new mutations arrive greatly influences the selection process.

"We've discovered a striking phenomenon that challenges a paradigm of molecular evolution," said Lahn, a genetics professor and Howard Hughes Medical Institute investigator. "As such, it may cause a significant shift in the field."

In the study, which appeared in the July issue of the journal Trends in Genetics, Lahn and his team compared so-called "synonymous" (Ks) and "nonsynonymous" (Ka) mutations in some 6,000 genes from various mammalian species.

Synonymous mutations do not affect protein structure, so natural selection is not a factor in their evolutionary which are naturally selected or rejected based on how they affect protein structure. …