Did Humans Get Their Big Brains From Neanderthals?

MCTFB writes, "According to CNN, human beings may have acquired a gene for developing bigger brains from Neanderthal man. Apparently, 70% of the world's population has a variant of a gene regulating brain size, with this variant being most common in people of European descent (where Neanderthal man lived alongside ancient humans), and least common in people of African descent (where Neanderthal man was non-existent). While modern day eugenicists might all too eagerly read into these findings to draw their own politically biased conclusions, people such as myself, who happen to be of northern European ancestry, may find it fascinating that somewhere in our lineage ancient humans and Neanderthals decided to make love and not war on the ancient plains of Eurasia."

Comments

Modern Humans and Neaderthal didn't interbreed

[nacnud75]

According to a study of Neanderthal mtDNA by Svante Pääbo et al Neanderthals and modern humans had a common ancestor 500 thousand years ago, this means Neanderthals and modern humans didn't interbreed.

Wasn't it known already that they interbred?

[angrytuna]

There was a Times article awhile back that involved the mating habits of Neanderthals and humans. It made that assumption from the analysis of the skeleton of a boy found in Portugal that had hybrid characteristics of the two groups.
From the article:

"This skeleton demonstrates that early modern humans and Neanderthals are not all that different," said Dr. Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis. "They intermixed, interbred and produced offspring."

Real Article

[GrumpySimon]

Rather than a crappy overview from CNN, here's the original article's abstract. In fact, it looks like it's in PNASes open access section, so you can all download the PDF for free.

They're basically studying a haplogroup of the microcephalin gene, and show that this gene probably entered the human lineage before 37KYA. The other haplogroups have coalescent times of circa 100KYA (which is around when Homo sapiens arose).

They then use some statistical magic to show that the early coalescence time for the D haplogroup was probably a result of introgression into the population - i.e. it came from another population. Note that they don't stress that it was Neanderthals, it could have been any archaic Homo lineage.

I'm not sure what to make of this yet, as far as I'm aware there's some very strong evidence AGAINST interbreeding between Neanderthals and Humans (e.g. Svante Paabo's work etc)