Thursday, June 16, 2005

UoC study overturns conventional theory in evolution

This just in:

New data suggest that the accumulation of genetic changes is not solely determined by natural selection. A study by University of Chicago researchers contradicts conventional theory by showing that the percentage of mutations accepted in evolution is also strongly swayed by the speed at which new mutations arrive at a gene: the faster the speed of new mutations, the greater the percentage of those mutations accepted.

"We've discovered a striking phenomenon that challenges a paradigm of molecular evolution that has been around for several decades," said lead author Bruce Lahn, PhD, assistant professor of genetics at the University of Chicago and Howard Hughes Medical Institute investigator. "As such, it may cause a significant shift in the field."

Please note that I am not claiming that this research refutes natural selection or evolution or anything of the sort. In fact, a careful reading of the title makes it clear that one aspect of the orthodox view of selection is being called into question, and not the whole neo-Darwinian synthesis. However, a reassessment of this aspect of molecular evolution may have big consequences for the understanding of the role of natural selection in evolution.

If this research is borne out, it makes patently clear just how uncertain many aspects of evolutionary theory are. The Darwinian is frequently left in the position of saying "I know that naturalistic evolution explains the origin of life and its variations, I just don't know how it does it." In the absence of a closely-reasoned explanation of molecular evolution fully supported at all points by evidence, the neo-Darwinian synthesis is held together by the conviction (whether metaphysical or merely methodological) that it all must be explained by naturalistic means only. Perhaps natural selection is the "theory of the gaps", holding place until the real explanation is discovered.

One scientist's assessment:

"Lahn and his associates have found a most striking result, one that is totally unexpected," said geneticist James Crow, professor emeritus of genetics and zoology at the University of Wisconsin-Madison. "If this result is indeed confirmed it would cast doubt on use of this ratio [Ka/Ks] as an indicator of selection."

Via this posting at William Sjostrom's AtlanticBlog.