Summary article regarding the genetic evolution of Europeans

[leonardo]

From Science magazine comes an article that summarizes the recent various findings regarding the evolution of Europeans regarding lactose persistence, height and skin pigmentation:
http://news.sciencemag.org/archaeolo...ved-white-skin.

Any thoughts on the article? In particular I focused on the development of height among, first northern, then central, Europeans being attributed to the Yamnaya culture.

[Jean M]

The article summarises two important papers from the team at the Reich Laboratory at Harvard University, which have generated a lot of commentary from bloggers and discussion on this forum. The papers were:

Wolfgang Haak et al., Massive migration from the steppe is a source for Indo-European languages in Europe, Nature, Published online 2 March 2015 and previously available online as a pre-print at bioRxiv.
http://www.nature.com/nature/journal...ture14317.html

Ian Mathieson et al., Eight thousand years of natural selection in Europe, bioRxiv preprint first posted online March 14, 2015.
http://biorxiv.org/content/early/2015/03/13/016477

It is the latter that covers the genetics of height in Europeans. The Yamnaya showed selection for height.

[Jean M]

Wolfgang Haak himself has written an amusing summary of the research in which he was involved and what aroused his interest in it:

Ancient DNA adds a piece to the PIE : https://acadadelaide.wordpress.com/2...ce-to-the-pie/

It’s no secret that the history of mankind has a fascination for me. As a boy, I used to make bows and arrows, spears and stone tools, hung out in the large woods behind our house in the German countryside, and read books about Stone Age mammoth hunters of Europe (I won’t mention the loincloth I made of rabbit skins). Now, I work in the field of ancient DNA, in the lucky position to apply my personal passion for the human past through the combined research interests of genetics and archaeology.

This is hard work on a day-to-day basis. Our rewards include publications, when we can share our hard work with others, as was the case this week. This study is the culmination of many years of work, and a real team effort, involving people that share the same passion and with whom I’m grateful to work. This study also touches on another childhood memory. I read up on Romans, Celts and Germans, and I learned that my mother tongue was somehow related to other languages as far away as India, which I thought must be on the other side of the planet. This blew my mind back then, and still does.

I now know that I am one of over three billion people who speak one of the 400 languages and dialects, which belong to the Indo-European language family. Among these are English, Italian, Greek, Armenian, Persian, and Hindi-Urdu. While the relationship between these languages is undisputed and had been recognised for a long time (long before my rabbit loincloths), there is a vivid debate about where this language family actually originated.....

.. it is clear that the steppe people must have added a piece to the PIE (pun intended!), even if it wasn’t the whole IE family, then at least some of its major branches. As always in science, new insights turn into new questions and we need to know what happened in those other regions, outside Europe, where IE is spoken today. This is not a simple undertaking, but we should remain optimistic. After all, I’m getting closer to answering the questions I had back in the loincloth days.

[Krefter]

Wolfgang Haak himself has written an amusing summary of the research in which he was involved and what aroused his interest in it:

Ancient DNA adds a piece to the PIE : https://acadadelaide.wordpress.com/2...ce-to-the-pie/

It's interesting to see this has been a passion for Haak since he was a kid, not just something he happened to be good at.

[Krefter]

From Science magazine comes an article that summarizes the recent various findings regarding the evolution of Europeans regarding lactose persistence, height and skin pigmentation:
http://news.sciencemag.org/archaeolo...ved-white-skin.

Any thoughts on the article? In particular I focused on the development of height among, first northern, then central, Europeans being attributed to the Yamnaya culture.

I doubt the potential for tall height can be marked accurately yet with DNA. At first glance I'm not going take the results too serios. The Pre-Historic Euros results in selective-markers is exciting because it proves humans are constantly evolving.

Many have a simplistic view that evolution is only about getting smarter and it happens very slowly. In the last few thousand years markers that were close to 0% are now dominate in the same populations. Evolving so that most people in a population are able to drink milk as adults is pretty serious adaption that happened recently in humans not some-type of animal.

In terms of pigmentation the markers we have today had been there since the Mesolithic(even hair color), but some people were similar to modern pops and some weren't, and I guess eventually the ones that weren't got wedded out(their phenotype was not their genes). IMO, Phe374Leu (rs16891982) is what got selected for the most even in the last 5,000-4,000 years.

https://docs.google.com/document/d/1...oIRagKyy8/edit

[Jean M]

I doubt the potential for tall height can be marked accurately yet with DNA.

Adult height is a complex mixture of nature and nurture. The genetic input is controlled by many genes, each of weak effect. Mathieson at al. 2015:

Under the pressure of natural selection, these variants are expected to experience small but correlated directional shifts, rather than any single variant changing dramatically in frequency, and recent studies have argued that this may be a predominant mode of natural selection in humans. The best documented example of this process in humans is height, which has been shown to have been under recent selection in Europe. At alleles known from GWAS to affect height, northern Europeans have, on average, a significantly higher probability of carrying the height-increasing allele than southern Europeans, which could either reflect selection for increased height in the ancestry of northern Europeans or decreased height in the ancestry of southern Europeans. To test for this signal in our data, we used a statistic that tests whether trait-affecting alleles are more differentiated than randomly sampled alleles, in a way that is coordinated across all alleles consistent with directional selection. We applied the test to all populations together, as well as to pairs of populations in order to localize the signal.

We detect a significant signal of directional selection on height in Europe (p=0.002), and our ancient DNA data allows us to determine when this occurred and also to determine the direction of selection. Both the Iberian Early Neolithic and Middle Neolithic samples show evidence of selection for decreased height relative to present-day European Americans. Comparing populations that existed at the same time, there is a significant signal of selection between central European and Iberian populations in each of the Early Neolithic, Middle Neolithic and present-day periods (p=0.011, 0.012 and 0.004, respectively). Therefore, the selective gradient in height in Europe has existed for the past 8,000 years. This gradient was established in the Early Neolithic, increased into the Middle Neolithic and decreased at some point thereafter.

Since we detect no significant evidence of selection or change in genetic height among Northern European populations, our results further suggest that selection operated mainly on Southern rather than Northern European populations. There is another possible signal in the Yamnaya, related to people who migrated into central Europe beginning at least 4,800 years ago and who contributed about half the ancestry of northern Europeans today. The Yamnaya have the greatest predicted genetic height of any population, and the difference between Yamnaya and the Iberian Middle Neolithic is the greatest observed in our data. This observation is consistent with archaeological evidence that the Yamnaya were taller than populations contemporary to them.

[Jean M]

In terms of pigmentation the markers we have today had been there since the Mesolithic

Apart from blue eyes, only in Scandinavia. There was no migration from Scandinavia which would have spread pale skin southward in the Neolithic. By contrast farmers with pale skin were spreading almost over all over Europe in the Neolithic. So the logical deduction is made by Mathieson et al 2015:

We also found evidence of selection at two loci that affect skin pigmentation. The derived alleles of rs1426654 at SLC24A5 and rs16891982 at SLC45A2 are, respectively, fixed and almost fixed in present day Europeans. As previously reported, both derived alleles are absent or very rare in western hunter-gatherers. suggesting that mainland European hunter-gatherers may have had dark skin pigmentation. SLC45A2 first appears in our data at low frequency in the Early Neolithic, and increases steadily in frequency until the present, when it has frequency 1 in all populations except Spanish. In contrast, the derived allele of SLC24A5 increases rapidly in frequency to around 0.9 in the Early Neolithic, suggesting that most of the increase in frequency of this allele is due to its high frequency in the early farmers who migrated to Europe from the southeast at this time, although there is still strong evidence of ongoing selection after the arrival of farming.

The derived allele of rs12913832 at the HERC2/OCA2 locus is the primary determinant of blue eyes in Europeans, and may also contribute to light skin and hair pigmentation. Our analysis detects a genome-wide signal of selection at this locus, but instead of the signal being one of positive selection with a coefficient of 0.036 as in a previous study of ancient DNA in the eastern Europe steppe, our signal is of weakly negative selection. One possible explanation is local adaptation: that the allele is advantageous in the north and disadvantageous in the south of Europe. This hypothesis is supported by the fact that our data shows that an extreme north-south gradient in allele frequencies has been maintained in Europe for the last 8,000 years.

We find a surprise in seven Scandinavian hun er-gatherers from the Motala site in southern Sweden who lived around 7,700 years before present. While the western hunter-gatherers of central and southern Europe largely have the ancestral allele at the two major European skin pigmentation loci, the closely related Scandinavian hunter-gatherers have both the derived alleles contributing to light skin pigmentation at high frequency. Thus, the derived allele of SLC24A5 was common in both the Scandinavian hunter-gatherers and Early European farmers, but not in the geographically intermediate western hunter-gatherers.

[Krefter]

Apart from blue eyes, only in Scandinavia. There was no migration from Scandinavia which would have spread pale skin southward in the Neolithic. By contrast farmers with pale skin were spreading almost over all over Europe in the Neolithic. So the logical deduction is made by Mathieson et al 2015:

Both the Samara_HG and the Kareilia_HG are inferred to have light skin, like most of the Motala_HGs. So, it wasn't only a Swedish thing during the Mesolithic.

https://docs.google.com/document/d/1...?usp=drive_web

We know EHG and SHG-types are probably the main source of ANE in Europe today, so they like EEF can be a source for light skin-alleles. SHG may be apart of the "pre-Yamna" blood in Europeans, especially in Balts who have strangely high WHG(higher than anyone besides Mesolithic genomes).

Even though I don't know much about evolution, I doubt there's one or two sources genetic sources, and that it was selection that acted on pops no matter whether they were Yamna-like, French-like, etc. All I'm saying is it's possible EHG and SHG are a source for light skin.

[Jean M]

Both the Samara_HG and the Kareilia_HG are inferred to have light skin, like most of the Motala_HGs.

Inferred by whom? For me your link just leads to a document with links I can't open.

[Krefter]

Inferred by whom?

What I mean is both had the two major light skin mutations discussed in Mathieson et al 2015. My point was it wasn't only EEF and SHG who had both.