Wednesday, November 08, 2006

Could our Big Brains Come from Neanderthals?

Neanderthals may have given the modern humans who replaced them a priceless gift -- a gene that helped them develop superior brains, U.S. researchers reported on Tuesday.

And the only way they could have provided that gift would have been by interbreeding, the team at the Howard Hughes Medical Institute and the University of Chicago said.

Lahn's team found a brain gene that appears to have entered the human lineage about 1.1 million years ago, and that has a modern form, or allele, that appeared about 37,000 years ago -- right before Neanderthals became extinct.

"The gene microcephalin (MCPH1) regulates brain size during development and has experienced positive selection in the lineage leading to Homo sapiens," the researchers wrote.

The researchers reached their conclusions by doing a statistical analysis of the DNA sequence of microcephalin, which is known to play a role in regulating brain size in humans. Mutations in the human gene cause development of a much smaller brain, a condition called microcephaly.
I love these scientists doing the statistical analysis of the DNA. First they have humans interbreeding with chimpanzees for millions of years and now we are interbreeding with Neanderthals.

via Reuters

2 comments:

crush41 said...

This ties into Lahn's earlier discovery of ASPM and microcephalin, found primarily in Europeans and absent most of sub-Saharan Africa.

I'm a little skeptical on how homo sapiens and Neanderthals would've interbred on any large scale, since social groups were probably no larger than 150 during all of the Neanderthal's existence, and virulently hostile to one another. But as our ancestors pushed through the Near East and into Europe, we may have enslaved some of the vanguished Neanderthals (particularly the women) and interbred with them. Conceivably, it wouldn't take too much interbreeding before alleles for greater brainpower would spread like wildfire through the groups of our European ancestors.



Our 10,000 year-plus struggle with the fierce Neanderthals may have left some sweet spoils.

Fat Knowledge said...

crush,

When I was writing this, I thought you might bring that up. I agree with you that it is possible (although I would tend to go with the 'beer goggles' theory over the enslavement one).

I am just skeptical of these statisticians that make these claims because it fits their models well without any additional information. But they are sequencing the Neanderthal DNA as we speak, so we will know more soon.

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