Could our big brains come from Neanderthals? (Reuters/CNN)

[eppur_se_muova]

WASHINGTON (Reuters) -- 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 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.
***
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.
***
more: http://www.cnn.com/2006/TECH/science/11/08/neanderthals.brains.reut/index.html

Neanderthals are starting to look pretty good. Neocons, on the other hand, look worse than ever.

[aquart]

1. Cool. I always wanted to include them in the family.

[Union Thug]

2. Funny, as a once anthropology major, I've always loved the idea!

[aquart]

3. How could you not?

Nice religious people. Worshipped bears and ate them.

Lotta Republicans worship Bush, you know.

[ToolTex]

4. Let us wish them Bon appétit.

n/t

[Dead_Parrot]

5. We got the brains, but who got the looks?

[Igel]

6. Of course, it relies on post hoc reasoning.

What they'd need to do is sequence Neandertal DNA, something not likely to happen with any great reliability, and show that the crucial change was shared.

Otherwise they're simply arguing that after a bunch of mutations in Africa before 50k BCE, and in the face of many other mutations after the African exodus (if there was only one) took place, this could not have been a mutation within H. sapiens sapiens.

After all, there were at least 13k years in the Middle East and in Europe when the gene, if it was Neandertal, did not jump species. Then, suddenly, just a few thousand years before extinction (or when we peg their extinction), the gene jumps.

You'd expect the gene frequency to be greater where it originated, if it provided a non-environment-specific advantage. Moreover, there was precious little cross-breeding between Eurasians and sub-Saharan Africans. (It would be interesting to see how prevalent it was in the New World, if it made it to NE Asia before the migrations to N. America occurred, and how it patterns with blood group anomalies on the American West Coast.)

It's certainly in the realm of possible. Not even in the realm of very likely, unless this article leaves out some crucial information.

[mainegreen]

7. I believe they're working on sequencing Neandertal DNA now.

Be interesting to see what they find!

[Igel]

9. Indeed.

But it's likely that they'll be missing chunks of the genome. I hope not, though. Nothing like direct observation and comparison to make hash of deductive reasoning.

[Odin2005]

8. Oh for Christ's sakes, what kind of crap logic is this?

Thier reasoning is because this allele appeared around the same modern humans began to populate Europe in considerable numbers and Neandertals died out it MUST of originated in Neandertals. :eyes:

I've already read about this mutation in a recent book on human evolution called Before the Dawn, it has NOTHING to do with interbreeding with Neandertals. I'm starting to think this obsession with wanting to think we interbred with Neandertals comes from a desire to deny the fact that we outcompeted the Neandertals into extinction.

[Boomer]

10. Supplemental articles from science blogs

http://scienceblogs.com/pharyngula/2006/11/granpappy_was_a_neandertal.php

Granpappy was a Neandertal

Category: Evolution • Genetics • Molecular Biology • Science
Posted on: November 8, 2006 10:02 AM, by PZ Myers

Fascinating stuff…read this paper in PNAS, Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage, or this short summary, or John Hawks' excellent explanation of the concepts, it's all good. It's strong evidence for selection in human ancestry for a gene, and just to make it especially provocative, it's all about a gene known to be involved in brain growth, and it's also showing evidence for interbreeding between Homo sapiens and Neandertal man.

The short short explanation: a population genetics study of a gene called microcephalin shows that a) it arose and spread through human populations starting about 37,000 years ago, b) this particular form of the gene (well, a small cluster of genes in a particular neighborhood) arose approximately 1.1 million years ago in a lineage distinct from that of modern humans, and c) the likeliest explanation for this difference is that that distinct lineage interbred with modern humans 37,000 years ago, passing on this particular gene variant that was then specifically selected for, a process called introgression.

The work looks sound to me, and I'm convinced. The one thing to watch for, though, is that there will be attempts to overreach and couple possession of this gene to some kind of intellectual superiority. We don't know what this particular variant of the gene does yet! All we can say at this point is that some abstract data shows that a particular allele spread through the human population at a rate greater than chance would predict, that the gene itself has as one of its functions the regulation of brain growth, but that it is highly unlikely that that particular function is affected by the variant. Whatever it does, I expect the role is more along the lines of subtle fine-tuning rather than simply making people smart.

(snip)

http://scienceblogs.com/gnxp/2006/11/neandertal_humans_introgressio.php

Neandertal & humans - introgression

Category: Genetics
Posted on: November 8, 2006 9:46 AM, by Razib

I've been talking about introgression for a year right now. I've been waiting for the papers on this topic to come out, and the first has. If you haven't, please read the posts from Greg and John Hawks. Another paper is on the way, and Hawks promises something within this week. I strongly suspect that the Paabo group also has something up their sleeves. As I noted earlier the paper from Lahn et. al. is open access, free to the public. Read it, it's an elegant and compact piece of work, and I think they make a compelling case for introgression of an allele implicated in brain development from archaic non-African populations into the expanding proto-modern Out-of-Africa groups.

(snip)