Wednesday, March 15, 2017

Farmer Moms, Pastoral Dads???

Image result for bronze age family

 Iosif Lazaridis, David Reich, Failure to Replicate a Genetic Signal for Sex Bias in the Steppe Migration into Central Europe, March 14, 2017
Goldberg et al., Familial migration of the Neolithic contrasts massive male migration during Bronze Age in Europe inferred from ancient X chromosomes, September 30, 2016

Were Bronze age Central Europeans the product of unions between Foreign Pastoral Men from the Eurasian Steppe and Native Farmer Women from Central/Eastern Europe? One study (Goldberg et al. 2016) says they were and the other says they weren't.

To determine if admixture between Steppe Pastrolites and European farmers was sex bias both studies estimated Steppe Pastrolite ancestry and European farmer ancestry in the X chromosome and autosomal chromosome of Bronze age Central Europeans.

But each used different methods to do so. Goldberg et al. 2016 used ADMIXTURE and the other used qpAdm. In my opinion qpAdm is a better method than ADMIXTURE. So although I'm undecided, if I had to guess I'd guess that Lazardis and Reich are correct.

Let's look at the mtDNA of Bronze age Central Europeans to see if there's any evidence of sex bias admixture.

Corded Ware. N=67.
mtDNA: Steppe 42% (28), Farmer 41% (27), Unknown 17% (12)
Y DNA: 100% Steppe.
Autosomal: ~75% Steppe, ~25% Farmer

Bell Beaker. N=42.
Steppe=38% (16), Farmer=36% (16), Unknown 26% (10)
Y DNA: 100% Steppe
Autosomal: ~50% Steppe, ~50% Farmer

Unetice. N=94
Steppe=36% (34), Farmer=28% (26), Unknown 36% (34)
Y DNA: 100% Farmer?(yHG I2, could be Steppe aswell)
Autosomal: ~60% Steppe, ~40% Farmer.

Keep in mind I counted originally hunter gatherer "WHG" mHG U5b as farmer. mtDNA data doesn't suggest admixture between Steppe Pastrolites and Native Central/East European farmers was sex bias except maybe in Corded Ware. At least 40% of Corded Ware mtDNA is of farmer origin but only 25% of their ancestry is.

mtDNA from modern Europeans in my opinion though does indicate sex bias admixture has occurred in European history. Specifically it indicates most of modern European mtDNA is "EEF" and "CHG", from the Neolithic Near East.

Is my mtDNA Farmer or Steppe?: If you want to know your mtDNA is of Eurasian Steppe Pastrolite or European Farmer origin email me your haplogroup to Most European mtDNA can be labelled as Steppe or Farmer. For example I know my mtDNA (U5b2a2) is from European hunter gatherers who were assimilated by farmers and my Y DNA (R1b) is of Steppe origin.

Sunday, March 12, 2017

Siberia, Past and Present

"West Siberia"=Green, "South Siberia"=Red

A decent amount of mtDNA from Siberia which dates between 6000 BC to 0 AD has been sequenced in the last 15 years or so. In this post I'll give a brief description of the similarities and differences between ancient and modern Siberians.

Below is a list of the ancient and modern Siberians which I'll compare to each other.

South Siberia
6800-5800 BPKitoi culture, N=40
5800-4000 BPSerovo-Isakovo-Glazkovo culture, N=16
2800-2000 BPAltai Scythians, N=34
ModernAltaians, N=110
ModernBuryats, N=386
ModernTuvinians, N=195
ModernKhakassians, N=110

West Siberia
6000-5000 BP, Ust Tartas and Odinivo Cultures, N=27
3800-3000 BPKrotovo, Andronovo, Barba cultures, N=44
ModernMansi, N=51
Modern, Tatars, N=220

Here's a link of mHG frequencies for the above populations; Siberia, Past and Present.

All of the primary East Asian mHGs; A, B, C, D, F, are represented in ancient Siberia except for B.

mHGs which link ancient Siberia to modern Siberia; C4a1, C5b1, D4b1, G2a, F1b, A8, U5a1d2b

mHGs unique to ancient Siberia; A10(West Siberia).
mHGs unique to modern Siberia; B, N9a, M7

South Siberia, Past and Present

mHG A is x2-x3 less popular in all the modern South Siberians than all the ancient South Siberians. mHG F was exceedingly more frequent in the ancient South Siberian Kitoi culture at 38% than in any other modern or ancient Siberians. All of their F belonged to F1b, a form of F which is more or less Siberian/North Asian specific today. F1b is frequent in modern South Siberians(~5%) but not a single Atali Sycthian belonged to F or F1b.

mHG G2a makes a significant mark on all the mtDNA in all of the ancient and modern South Siberians. In contrast modern and ancient West Siberians barely have any G2a. But G2a can be found at decent frequencies in parts of Eastern Asia.

C4a1 was quite common in Atali Sycthians(12%) as it is in modern Tuvinians(12%) and Tofalar(34%). The only modern South Siberians who don't have at least 5% C4a1 are the Altaians(0%).

Several  mHGs exist in modern but not ancient South Siberia. Here they are...
B(primary B4), N9a, M7, M8, Y.

Both B and M7 are frequent in Eastern Asia(Japan, China, Burma, Tawian, etc).

West Siberia, Past and Present

Like in South Siberia, in West Siberia mHG A frequencies are considerable lower in moderns than in ancients. The Ust Tartas and Odinivo Cultures' high frequency of Z(19%) differentiates it from all other ancient and modern Siberians. 0% of modern West Siberians have Z.

mHG F, mostly F1b, is present in modern West Siberians but is absent in ancient ones. M7 and B are present in modern but not in ancient West Siberians. Besides that all the major mHGs in modern West Siberians are present in ancient ones.

West Eurasian mtDNA

West Eurasian mtDNA is present in every ancient and modern Siberian population. Ancient Siberians' WE mtDNA belonged exclusively to mHG U(U5a, U4, U2e) until the appearance of the Afanasievo(3000 BC)  and Andronovo cultures(1800 BC) from Eastern Europe. They brought with them large amounts of H, U5a, U4, T2, T1a, and smaller amounts of other West Eurasian mHGs.

Up until 1000 BC all of the WE mtDNA found in Siberia looks like it's from Eastern Europe. In 1000 BC mHGs never found in Europe but frequent in Western and SC Asia appear; U1a, U7, J1b, and others. Possibly after migrations from Eastern Europe(eg, Afanasievo) peoples from SC Asia or the Caucasus migrated into Siberia. 

Sunday, March 5, 2017

First mtDNA from Mesolithic Sardinia; J2b1 and I3

Modi, A. et al. 2017 just published mito genomes of two 10,000 year old Mesolithic individuals from Sardinia. One belongs to J2b1 and one to I3. Neither belongs to hg U, the lineage which 97% of 100+ other Mesolithic European mtDNA samples belong to.

A J2 and a hg I dating around 10,000 years old have been found in the Near East. Their presence in Mesolithic Sardinia indicate Mesolithic Europe, maybe specifically Mediterranean Europe, exchanged genes with the Near East before Near Eastern farmers migrated en masse into Europe in the Neolithic.

Saturday, March 4, 2017

More ancient Eastern European mtDNA

Two new papers with ancient Baltic mtDNA: Saag et al. 2017 and Mittnik et al. 2017, were posted at bioRxiv yesterday. Together the two produced 29 new mtDNA samples from ancient Baltic hunter gatherers, 9 from Baltic Corded Ware, and 17 from the Baltic Bronze age. The new data has been added to my European Hunter Gatherers and Bronze age North Europe mtDNA spreadsheets.

The news results contain only a few pieces of interesting information.

  • Two Baltic HGs don’t belong to mHG U; H11a and K1b2
  • One Baltic HG belongs to “Saami” U5b1b1a
  • 47% of Bronze age individuals belong to mHG H
  • No Siberian mtDNA.

Regarding the Baltic hunter gatherer H11a and K1b2, both mHGs today are more or less European specific today. H11a peaks in Poles, not in a particular large region, which is interesting. Also K1b2 is well documented in Europe but to my knowledge only one non European(Armenia) is known to carry it.

In a post I made about Finnish mtDNA a few months ago I speculated that mHG U5b1b1a descends from ancient NorthEast European hunter gatherers. Well now there’s good evidence that is the case: Kretuonas4 an ancient NorthEast European hunter gatherer of the Narva culture belonged to U5b1b1a. Today U5b1b1a is NorthEast European specific but has also been found in locations such as England, Spain, and Turkey.

The new data suggests Baltic mHG frequencies changed in a big way after the Late Neolithic. Can you guess how? If you read my blog you should know. This will help you; Natural Selection Did It!. mHG H frequencies skyrocketed. I’ve been speculating for a while that for some reason in Bronze age Europe natural selection drove mHG H frequencies upand the frequencies of other mHGs like T2 and K down. mtDNA data from Iron age Poland, Scandinavia, and Spain also display high frequencies of H unlike earlier people from the same locations. My natural selection hypothesis is looking stronger and stronger.

Lastly not a single individual in these two studies belonged to an Siberian mtDNA haplogroup. As far as I know  the autosomal DNA from these ancient individuals don't suggest they had any Siberian-like ancestry either. So it looks like Siberian ancestry, possibly along with yHG N1c and Uralic languages, arrived in the Baltic during the Bronze age or later. Siberian mtDNA(C5b1, Z, D) dating 3,500 years old was found in Karelia. So maybe Siberian ancestry existed in some parts of NorthEastern Europe during the Bronze age and then it gradually expanded.