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Those criticisms are particularly important, Collins said, because Lahn's testing did find geographic differences in populations harboring the gene variants today.
They were less common in sub-Saharan African populations, for example.
Around this time, farming techniques began to spread out of Anatolia - now Turkey - across Europe and Asia, archaeological evidence shows.
The farmers themselves may have moved, or natives may have adopted words along with agricultural technology.
That the genetic changes have anything to do with brain size or intelligence "is totally unproven and potentially dangerous territory to get into with such sketchy data," stressed Dr.
Lahn and colleagues examined two genes, named microcephalin and ASPM, that are connected to brain size.
That does not mean one population is smarter than another, Lahn and other scientists stressed, noting that numerous other genes are key to brain development.
"There's just no correlation," said Duke's Wray, calling education and other environmental factors more important for intelligence than DNA anyway. The information contained in the AP News report may not be published, broadcast, rewritten or redistributed without the prior written authority of The Associated Press.
For the microcephalin gene, the variation arose about 37,000 years ago, about the time period when art, music and tool-making were emerging, Lahn said.
For ASPM, the variation arose about 5,800 years ago, roughly correlating with the development of written language, spread of agriculture and development of cities, he said.