Skip to comments.Could our big brains come from Neanderthals?
Posted on 11/07/2006 7:27:55 PM PST by Pharmboy
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.
Their study, published in the Proceedings of the National Academy of Sciences, provides indirect evidence that modern Homo sapiens and so-called Neanderthals interbred at some point when they lived side by side in Europe.
"Finding evidence of mixing is not all that surprising. But our study demonstrates the possibility that interbreeding contributed advantageous variants into the human gene pool that subsequently spread," said Bruce Lahn, a Howard Hughes Medical Institute researcher at the University of Chicago who led the study.
Scientists have been debating whether Neanderthals, who died out about 35,000 years ago, ever bred with modern Homo sapiens. Neanderthals are considered more primitive, with robust bones but a smaller intellects than modern humans.
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.
Positive selection means the gene conferred some sort of advantage, so that people who had it were more likely to have descendants than people who did not. Lahn's team estimated that 70 percent of all living humans have this type D variant of the gene.
"By no means do these findings constitute definitive proof that a Neanderthal was the source of the original copy of the D allele. However, our evidence shows that it is one of the best candidates," Lahn said.
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.
By tracking smaller, more regular mutations, the researchers could look at DNA'S "genetic clock" and date the original genetic variant to 37,000 years ago.
They noted that this D allele is very common in Europe, where Neanderthals lived, and more rare in Africa, where they did not. Lahn said it is not yet clear what advantage the D allele gives the human brain.
"The D alleles may not even change brain size; they may only make the brain a bit more efficient if it indeed affects brain function," Lahn said.
Now his team is looking for evidence of Neanderthal origin for other human genes.
Roast duck with mango salsa ping...
Yep, does sound like a Dem specimen for sure.
They currently reside in France if I'm not mistaken...
Well if they interbred they weren't different speicies at all.
Considering the election results of this night, Im not sure just how big our brains are. Or, if big brains mean anything.
From the article - They noted that this D allele is very common in Europe, where Neanderthals lived, and more rare in Africa, where they did not.
I may get myself banned for saying this, but consider where the "D Allele" is uncommon, and where the ancestral home of many of the Rat voters is.
Yeah, it's a bad night, doc. But two years of the Dems running the House can only help the GOP in 2008. Unless the Rats plan to keep Pelosi under wraps for two more years.
Good post, thanks. (We Are Neanderthals)
The entire proposition is a canard.
From Publishers Weekly
This uneven volume from University of Michigan anthropologists Wolpoff and Caspari defends Wolpoff's theory that human evolution resulted from long-term "multiregional evolution" rather than via a relatively recent descent from a single "Eve" in Africa. The authors largely base their case on the fossil record, which contains evidence that, they contend, doesn't jibe with the Eve theory, which was derived primarily through DNA analysis by molecular biologists. Their argument is well-reasoned but some of the basic concepts, including that of multiregional evolution, could use a clearer explication. Technical material abounds, much of it likely to prove difficult for the general reader. And, while Wolpoff receives top authorial billing, the text is presented mostly in the first-person singular from Caspari's perspective, an intrusive stylistic device. There's much to ponder here, though, and the middle chapters, which place paleoanthropology in a historical and political context, are sound and informative. Illustrations."
"Canard" is French for "duck," as in "roast duck with mango salsa."
I don't know if our ancestors interbred with Neanderthals, but I think that all the DNA studies so far have turned up negative for any Neanderthal DNA surviving in living human beings. The Neanderthals lived in a restricted area of the planet--Europe and part of the Middle East--and there were other human populations elsewhere. How can they tell the smart gene didn't originate in one of the other groups?
While we did learn in school that different species don't interbreed, that's not always the case. Different species don't typically interbreed, but there are examples where that does happen. Horse and donkey = (sterile) mule. And several years ago two different species of siamangs (a type of Asian ape) interbred and had viable offspring. The unique thing about these siamangs is that the two species had different numbers of chromosomes.
I'm not quite sure, Ben. We have genes and features in our bodies that are more at home in cats or birds than in us. How that happens is difficult to explain, but it seems to be true.
Ah -- as for cats . . . . those pesky pussies maanged to transfer some genes over by way of virus.
That is impressive actually. I wonder what the chromosome counts are for lions and tigers which can interbreed for make ligers (absolutely HUGE cats) and tigons?
Brain size doesn't always matter. The last I knew elephants had huge ones but they're not doing too well tonight.
Correct. But, the measure that counts for more is the ratio of brain size to body size. We win that one over all other species--by far. Including Dumbo.
Well, yes, But viral transfer is the tool used by gene therapists even today.
They can't. I think it is a very remote possibility that our ancestors interbred with hairy, smelly Neanderthals.
Just Google "Almas" and you'll see what I mean.