Monday, March 6, 2017

A Week of DNA, some fallout

Drip, drip

In the ancient days of genetic genealogy (like ten years ago) it was hypothesized that the division of modern European haplogroups had formed during the Bell Beaker phase (R1b) in Western Europe, and the Corded Ware Culture (R1a) in Eastern Europe.

That was before a single ancient individual had been sequenced.  Now we sit befuddled that what we thought was true is in fact uniformly true, weirdly uniform.  The resolution is increasing and here's a few implications from last week.


Afanasievo:

The Early Bronze Age Afanasievo are so far mostly or likely R1b M269, although one later Afanasievo man from Mongolia was Q-242  (Clemence Hollard, 2016)  possibly representing the shift to the Okunev era.

This should not be surprising since Afanasievo is basically Yamnaya in another place, but now that the Y-chromosomes are published, we can confirm that, yes, they are identical.  (See also Bernard's blog)

The major implication is illustrated by distance.  It is approximately 1,684mi (2709km) from Samara to Minusinsk, Russia.  Let's pretend a moment for the sake of argument, that M269 L151/P310 in the West has a more recent origin in the Caspian steppe:

As the crow flies, from Samara, Russia it is approximately
- 3,826 miles to El Hierro, Canary Islands (R1b ~50% of Pre-Hispanic Bimbaches)
- 3,556 miles to Maroua, Cameroon (5723km) (90% of herdsmen) 
- 2,802 miles to Porto, Portugal (4509km)  (~83%)
- 2,327 miles to Minoreca, Baleric Islands (3745cm)  (73%)
- 2,102 miles to Iverness, Scotland (3383)  (~90% or higher along Irish Sea)

Now I say "for the sake of argument" since everyone seems to go bananas on this subject.  But the powerful implication here is each of these places was indisputably transformed at the cusp of the Bronze Age by dairy herder migrants.  Each of these places has experienced incredible male biased gene-flow, which is why we have the spectrum we have, yet all having youthful sub-clades.  And it just so happens that the people of the Minusinsk Basin can be shown (almost empirically) to originate in the Samara region of Russia at about the same time as the beginning of the Beaker phenomenon.

Now it could be that the genetic origins of the proto-Beakers is clarified very soon, but I have a feeling that the plot will only thicken.  That is unless it is shown that Protruding Foot Beakers west of the Rhine were all L51, then we'll have some kind of complicated Ruckstrom.

The other implication is that the means to confidently travel great distance becomes an unavoidable issue in the forefront.  Before jumping to conclusions, however, let me caution that the formation of the Beaker Culture is more complicated that a map with arrows pointing in different directions.  The Beaker Culture is a unique international animal and it will continue to puzzle for a while.

More Corded Ware Culture:

A new paper on Baltic Corded Ware shows are all R1a, which was apparently uniform (again recently in Poland) across the Corded Ware horizon and its derived cultures.  The surprising uniformity across many different cemetaries suggests a social structure similar to the Beaker Culture and its descendant cultures.

Supercession, youth and uniformity:

This article last week by Ann Gibbons, "Thousands of horsemen may have swept into Bronze Age Europe, transforming the local population" is the latest volley concerning the disparity of uni-parental lineages in Europe.

This is not a new issue, and despite new analysis from ancient DNA, the situation hasn't changed.  The question is the mechanism for the paternal change. One explanation may be elite sex bias, as can be demonstrated in Mexico from a new paper: DNAeXplained blog.

Mesolithic Sardinia:

Only two lineages are sequenced, but they look to me like they could be out of the Gulf area. 

Iron Age Scythians and Sarmatians:

A number of genomes from the Scythian and Sarmatian cultures were published Eurogenes again
and again.  It appears that a massive transition happened in the steppe away from the Yamnaya/Afanaseivo type population toward one more CWC/Androvono/Scythian type.


Expect more cracks in the dam.



3 comments:

  1. However goat herding was dominant in Afansievo, was it not ?

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    1. Well I would emphasis that it is the earliest cattle in the area regardless if goats dominant remains. And honestly El Hiello was probably settled in the Iron Age by Atlas Berbers, but my main point is really time and distance.

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  2. There are two key apparent facts. One is the association of y chromosome haplogroup R1b with Bell Beakers, people living on the South Russian steppes just North of the Caucasus Mountains, at Samara on the Volga River near the South Ural Mountains and as part of the Afanasievo culture adjacent to the Altai mountains. The other is the connection of these people with the emergence of the bronze age. The increasing importance of metal meant a need for long distance trade and for people who specialized in working with the metal. The first major European culture centered on bronze was at Maikop. The most likely logic was a source in the Caucasus Mountains of copper mixed naturally with the right amount of arsenic to form a good bronze alloy. The Maikop people were very likely to have been R1b. Increased mobility was both a requirement and a consequence of the bronze age. Better metal lead to better tools, ox drawn wagons, and better boats. No doubt the people who spread across the steps from Samara to the Altai Mountains lived off cattle. But their motivation in settling near the mountains probably had more to do with its metal ore than with its grass. There is no doubt about the utility of late bronze age boats. Agamemnon brought 1,000 of them to Troy. The bronze age wreck found at Uluburun carried 20 tons of metal. Maritime trade between the Aegean and the Black Sea was the logic of Troy's location. Troy goes back to 3,000 BCE. The Bell Beakers were spread along the Western Mediterranean Coast of France and Spain, the Atlantic Coast, and the European river system. They were people who brought the bronze age to Western Europe and who were involved in the commercial activities it generated. They appeared at a time around 2500 BCE long after the bronze age emerged at Maikop. There probably never will be any certain way to know their source. But, the obvious one given their genetics and their mobility is the Northern shore of the Black Sea where a metal based economy was already a thousand years or so old.

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