Saturday, January 09, 2010

Genetics of hunter-gatherers and early farmers in Europe

I'm back, and will try to be more regular about posting. This paper came out a few months ago in Science and I've been meaning to look at it for a while.
They examine the Fst in mtDNA sequence between hunter-gatherer samples (13,400 to 2,300 ago) in Central Europe, from more recent individuals (and modern Europeans). I guess they must use archaeological or other evidence to determine their subsistence pattern.
They get an Fst of 0.163, which is indeed remarkably high - although do we really know what to expect when comparing populations over time? To answer this, they perform some simulations, and reject the hypothesis that this Fst could have been due to a process of population continuity.
Along with their discussion of the haplotype differences betwee the hunter-gatherers and farmers, this result is pretty interesting and suggests a migration of early farmers into central Europe and replacement of hunter-gatherers.
Proto-Indo-Europeans?

Genetic discontinuity between local hunter-gatherers and central Europe's first farmers.
Bramanti B, Thomas MG, Haak W, Unterlaender M, Jores P, Tambets K, Antanaitis-Jacobs I, Haidle MN, Jankauskas R, Kind CJ, Lueth F, Terberger T, Hiller J, Matsumura S, Forster P, Burger J.
Science 2009 Oct 2;326(5949):137-40.
Abstract: After the domestication of animals and crops in the Near East some 11,000 years ago, farming had reached much of central Europe by 7500 years before the present. The extent to which these early European farmers were immigrants or descendants of resident hunter-gatherers who had adopted farming has been widely debated. We compared new mitochondrial DNA (mtDNA) sequences from late European hunter-gatherer skeletons with those from early farmers and from modern Europeans. We find large genetic differences between all three groups that cannot be explained by population continuity alone. Most (82%) of the ancient hunter-gatherers share mtDNA types that are relatively rare in central Europeans today. Together, these analyses provide persuasive evidence that the first farmers were not the descendants of local hunter-gatherers but immigrated into central Europe at the onset of the Neolithic.

8 comments:

Maju said...

Welcome back. :)

I must say I find Bramanti's paper pretty good in the context of what has been done on aDNA. They bothered checking for coding region mutations, resolving nearly all doubts re. the haplogroup adscription (HVS-only research is what has dominated the field and leaves way too many incognites). However some of the populations they study are in fact hunter-gatherers from the Neolithic period and very possibly reverted hunter-gatherers with a direct connection with the Dniepr-Don Neolithic. But at least the Swabian data is from true Paleolithic and Epipaleolithic peoples and that is quite revealing.

Another limitation is that they use Haaks' data for Danubian Neolithics, and this is based on HVS-only sequences and oversampled certain (minor and peripherical) region of East Germany. So the conclusions are not so clear after all.

Proto-Indo-Europeans?

Probably not.

I have reviewed all the aDNA data for Europe in this post and late Chalcolithic/Bronze Kurgan-derived IEs have different signatures, with much less T and no N1a anymore (instead K and H are dominant but varying from place and specially period, U5 also reappears for Urnfields Low Saxony).

Yann Klimentidis said...

Thanks for the info Maju.

Amber Faith said...

Fascinating blog in every aspect and article... sidebar question from an artist who paints paleo-scenes and subjects: are there any specific ethnic groups/haplo or otherwise, who possess a discernable sagittal keel?
I know a white Welsh-Scots-Nordic father and son, both have modeled for me, who ( like actor Patrick Stewart) have distinct sagittal keels. The father's keel was especially strong. Both men are 6/6" and 6'8" respectively and have strong jaws. I understand the keel is related to jaw/bite power.
The keels so fascinate me ( thinking of Neander & Heidelberg pates...lol) ..then I read only a few modern humans have this feature. Any info or ideas?
Thanks..........Amber

Yann Klimentidis said...

Amber, I don't know how common sagittal keels are among modern humans. They're probably like big brow ridges or other ancestral traits that show up every now and then. I coulnd't speculate as to what ethnic group would have more of these but if it's a neanderthal like trait then one might think that they would happen more often in Europeans since there may have been gene flow between moderns and neanderthals in Europe. Sorry can't be of more help.
Yann

Amber Faith said...

Thanks Yann...I appreciate your kind reply. Since human skulls have been such perennial elements in my paintings of Neolithic/megalithic British sites for four decades, they prompt anatomical questions only the genome projects might explain.My subjects' sagittal keels were not splendid crests, like Neanderthals. They are more subtle, like a flattened cord of bone running front nearly to back. Both men reported unusual molar, bicuspid and wisdom tooth roots also... and shocked dentists. ;) lol Also, both men reported to me surviving, unconcussed, direct head traumas in severe past accidents.
it has always puzzled me. Now with the newly-announced results of N + MH mixing, the Y-line mysteries of my favourite models may be explained.
I am now hooked on your blog posts!
cheers!
Amber

Lou Alvis said...

Amber, i posted in an unrelated blog here, about the newest studies of genetic signals of neanderthal in modern human populations.
http://www.eurekalert.org/pub_releases/2010-05/uoc--ngy042810.php

though this study is inconclusive as regards significant functional operation of this genetic signal, (only 1-4%) it does leave open the door to possible morphological changes and traits ) e.g. RDH-MC1 variant. I have a special interest in early human populations in west Eurasia, with emphasis on population replacement and genetic bottlenecking. Always weilling to share data.
I have seen this sagittal crest myself , in very small percentages of the population, as well as other anomalous cranial features.
I would love to look at your Illustrations, hopefully you have posted some online
and I too am now hooked on Yann's delightful blog.

price per head said...

Another limitation is that they use Haaks' data for Danubian Neolithics, and this is based on HVS-only sequences and oversampled certain (minor and peripherical) region of East Germany. So the conclusions are not so clear after all.

Mack Louwagie said...

To anyone who may read this, I may have some insight into saggital keels. All the men in my family display pronounced saggital keels along with broad chins and naturally immense necks (My saggital keel at its highest is an inch above the smooth surface of my skull, starting at the beggining of my hairline and tapers down naturally with the back of my skull)

There is a large amount of evidence pointing towards my family having Indo-European roots but still speculation. Also a blood test of the patriarchal members of my family stated we had "abnormal amounts of Neanderthal DNA".

But who's to say it's connected. (Also my cousins born of the matriarchal side of the family do not share this characteristic, it seems to be strictly contained to the Y gene)

 
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