Thursday, November 09, 2006

Neanderthals in the Gene Pool

Well that didn't take long. Remember my post last week that discussed possible Neanderthal/modern human interbreeding based on skeletal morphology evidence? You may recall, I figured that genetic evidence would tell the tale.

Today Nicholas Wade of the New York Times reports on a study that finds circumstantial evidence that a gene for brain size now present in most of the world's population came from Neanderthals. From the article:

"Both genetic and fossil studies show that anatomically modern humans emerged 200,000 years ago in Africa and migrated into Europe 40,000 years ago. In about 10,000 years, Europe’s longtime inhabitants, Neanderthals, became extinct. The mainstream interpretation is that modern humans somehow replaced them without interbreeding.

In previous research, Dr. Lahn and associates discovered that a gene for brain size called microcephalin underwent a significant change 37,000 years ago. Its modified variant, or allele, appeared to confer a fitness advantage on those who possessed it. It is now present in about 70 percent of the world’s population.

The new research focused on the two classes of alleles of the brain gene. One appeared to have emerged 1.1 million years ago in an archaic Homo lineage that led to Neanderthals and was separate from the immediate predecessors of modern humans. The 37,000-year date for the other variant immediately suggested a connection with Neanderthals."

Apparently more DNA studies about modern humans interbreeding with Neanderthal and other archaic humans are due out soon. The ever-reliable John Hawks Anthropology Weblog has lots of interesting things to say about this in a couple of posts.

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