Monday, December 17, 2007

Change Is At All Levels | The Question Is How Fast?

Science Now has an article on Human Evolution Is Speeding Up -- (Gibbons 2007 (12 10): 1 -- ScienceNOW)

Plentiful food has made it easier than ever before to survive and reproduce in many parts of the world, so it's tempting to think that our species has stopped evolving. But a controversial new study says that isn't so. Far from slowing down, human evolution has sped up in the past 40,000 years and has become 100 times faster in the past 5000 years alone, according to the analysis. This means that even though some people have been globe-trotters who interbreed, most humans on different continents are becoming more different, rather than blending together into one genetically homogenous race

The same subject is covered by the New York Times.
Natural Selection - Evolution - Genetics - New York Times Selection Spurred Recent Evolution, Researchers Say

The new survey — led by Robert K. Moyzis of the University of California, Irvine, and Henry C. Harpending of the University of Utah — developed a method of spotting human genes that have become more common through being favored by natural selection. They say that some 7 percent of human genes bear the signature of natural selection.

As well as from the Los Angeles Times: Study finds humans still evolving, and quickly. The pace has been increasing since people started spreading through Europe, Asia and Africa 40,000 years ago.By Karen Kaplan, Los Angeles Times Staff Writer December 11, 2007

The pace of human evolution has been increasing at a stunning rate since our ancestors began spreading through Europe, Asia and Africa 40,000 years ago, quickening to 100 times historical levels after agriculture became widespread, according to a study published today.

From Science Now : The findings are persuasive to anthropologist Clark Larsen of Ohio State University in Columbus. But not everyone is on board. "I don't deny recent rapid selection," says geneticist Kenneth Kidd of Yale University. "But I am not yet convinced that so much rapid selection at so many places in the genome has occurred. ... I think we need much more data."

From the New York Times: David Reich, a population geneticist at the Harvard Medical School, said the new report was “a very interesting and exciting hypothesis” but that the authors had not ruled out other explanations of the data. The power of their test for selected genes falls off in looking both at more ancient and more recent events, he said, so the overall picture might not be correct.

Similar reservations were expressed by Jonathan Pritchard, a population geneticist at the University of Chicago.

“My feeling is that they haven’t been cautious enough,” he said. “This paper will probably stimulate others to study this question.”

From the LA Times: "The advantage of all but about 100 of the genes remains a mystery, said University of Wisconsin-Madison anthropologist John Hawks, who led the study...If there were not a mismatch between the population and the environment, there wouldn't be any selection," Hawks said. "Dietary changes, disease changes -- those create circumstances where selection can happen."

It is the other resources provided by Science Now that have the more in-depth argument from John Hawks:

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