A reappraisal of Ashkenazic maternal ancestry

Kevin Brook, who occasionally comments on this blog, has published a peer-reviewed book titled The Maternal Genetic Lineages of Ashkenazic Jews.

The book focuses on 129 mitochondrial (mtDNA) haplogroups that are found in present-day Ashkenazic Jews, and reveals that these lineages can be traced back to a wide range of places, such as Israel, Italy, Poland, Germany, North Africa, and China.

Ergo, it argues that both Israelites and converts to Judaism from a variety of gentile groups made lasting contributions to the Ashkenazic maternal gene pool. In Kevin's own words, the book also:

- shows that all Ashkenazim remain genetically linked to a significant degree to other types of Jewish populations, not only paternally but maternally as well

- disproves the myth that Cossack rapists were responsible for any of the non-Israelite DNA in Ashkenazim

- presents new DNA evidence in favor of a small contribution of Khazarian and Alan converts to Judaism to the Ashkenazic gene pool.

That makes good sense based on what I've learned over the years from studying modern and ancient genome-wide Ashkenazic DNA. More information about Kevin's book is available at the Khazaria.com website HERE.

See also...

My take on the Erfurt Jews

The PIE homeland controversy: January 2019 status report

Last year, the preprint that claimed to have presented archaeogenetic data that opened up the possibility of the Proto-Indo-European (PIE) homeland being located south of the Caucasus was, ironically, also the preprint that considerably strengthened my confidence that the said homeland was actually located north of the Caucasus.

Of course, I'm talking about the Wang et al. manuscript at bioRxiv, which is apparently soon to be published as a peer-reviewed paper in Nature Communications (see here).

It'll be fascinating to observe if and how the peer-review process has impacted on the preprint, and especially its conclusion. My impression was that the authors seemed pretty sure that the Maykop people gave rise to the Yamnaya culture, or at least Indo-Europeanized it. But, as far as I saw, the archaeogenetic data didn't bear this out at all, and instead showed a lack of any direct, recent and meaningful genetic relationship between Maykop and Yamnaya (see here). Was this also picked up by the peer reviewers? We shall see.

Moreover, there was some exceedingly interesting fine print in the manuscript's supplementary information:

Complementary to the southern [Darkveti-Meshoko] Eneolithic component, a northern component started to expand between 4300 and 4100 calBCE manifested in low burial mounds with inhumations densely packed in bright red ochre. Burial sites of this type, like the investigated sites of Progress and Vonyuchka, are found in the Don-Caspian steppe [10], but they are related to a much larger supra-regional network linking elites of the steppe zone between the Balkans and the Caspian Sea [16]. These groups introduced the so-called kurgan, a specific type of burial monument, which soon spread across the entire steppe zone.

Always read the fine print, they say. And they're right. Imagine if I only read the preprint's conclusion and missed this little gem; I'd probably think that the PIE homeland was located south of the Caucasus rather than on the Don-Caspian steppe.

Wow, proto-kurgans with inhumations densely packed in bright red ochre? A supra-regional network linking the elites of the steppe all way from the Balkans to the Caspian Sea? An expansionist culture? And, as evidenced by the ancient DNA from the Progress and Vonyuchka sites, a people who may well have been in large part ancestral to the Yamnaya, Corded Ware and Andronovo populations, that have been identified based on archeological and historical linguistics data as the main vectors for the spread of Indo-European languages as far as Iberia in the west and the Indian subcontinent in the east.

I wonder if the authors actually asked themselves who these people may have been, before so haphazardly turning to Maykop and, ultimately, the Near East, as the likely sources of the Yamnaya culture? To me they look like the Proto-Indo-Europeans and true antecedents of Yamnaya.

So as things stand, my pick for the PIE homeland is firmly the Don-Caspian steppe. And I genuinely thank Wang et al., and indeed the Max-Planck-Institut für Menschheitsgeschichte (aka MPI-SHH), for their assistance.

But, you might ask, what about the Hittites? Yes, I realize that no one apart from me and a few of my readers here can find any steppe ancestry in the so called Hittite genomes published to date. However, consider this: if the PIE homeland really was on the steppe, and a dense sampling strategy of Hittite era Anatolia fails to turn up any unambiguous steppe ancestry in at least a few individuals, then there has to be an explanation for it. But let's wait and see what a dense sampling strategy of Hittite era Anatolia actually reveals before we go that far.

See also...

The PIE homeland controversy: August 2019 status report

Yamnaya: home-grown

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...

Big deal of 2018: Yamnaya not related to Maykop

I was going to write this post after the genotype data from the Wang et al. preprint on the genetic prehistory of the Greater Caucasus became available, because I wanted to demonstrate a few key points with analyses of my own. But I've got a hunch that the formal publication of the manuscript, and thus also the release of the data, has been indefinitely delayed for one reason or another. So here goes anyway, the big deal of 2018...

This year, ancient DNA has revealed that the populations associated with the Maykop and Yamnaya archeological cultures were genetically distinct from each other, and, in all likelihood, didn't mix to any significant degree. Case in point: an ADMIXTURE analysis from Wang et al. 2018.

No doubt, this is quite a shock for many people, especially those of you who consider Maykop to have been a Proto-Indo-European-speaking culture that either gave rise to Yamnaya or at least Indo-Europeanized it. So now, if you still want to see Maykop as the Indo-Europeanizing agent in the Pontic-Caspian steppe, you'll have to rely solely on archeological and linguistics data, and also keep in mind that ancient DNA has slapped you in the face.

In just a few years, ancient DNA has provided us with plenty of shocks, but this is arguably among the biggest.

However, I honestly can't say that it was a huge surprise for me, because I tentatively predicted this outcome more than two years ago based on a handful of mitochondrial (mtDNA) haplotypes (see here). Certainly, analyzing genome-wide genetic data is what I thrive on, but if that's off limits, then eyeballing even a few mtDNA markers can also be very useful.

Wang et al. easily demonstrate the lack of any meaningful genetic relationship between Maykop (including Steppe Maykop, which shows an unusual eastern influence) and Yamnaya using a range of methods. But, judging by their conclusion, in which they still seem to want to see Maykop as the said Indo-Europeanizing agent in the Pontic-Caspian steppe, they're not exactly enthused by their own results. And they also make the following claim (emphasis is mine):

Based on PCA and ADMIXTURE plots we observe two distinct genetic clusters: one cluster falls with previously published ancient individuals from the West Eurasian steppe (hence termed ‘Steppe’), and the second clusters with present-day southern Caucasian populations and ancient Bronze Age individuals from today’s Armenia (henceforth called ‘Caucasus’), while a few individuals take on intermediate positions between the two. The stark distinction seen in our temporal transect is also visible in the Y-chromosome haplogroup distribution, with R1/R1b1 and Q1a2 types in the Steppe and L, J, and G2 types in the Caucasus cluster (Fig. 3A, Supplementary Data 1). In contrast, the mitochondrial haplogroup distribution is more diverse and almost identical in both groups (Fig. 3B, Supplementary Data 1).

I'd say that what they're almost suggesting there is that the Caucasus and Steppe clusters, hence also the Maykop and Yamnaya populations, shared significant maternal ancestry. If this were true, then perhaps it might mean that the Pontic-Caspian steppe was Indo-Europeanized via female-biased migrations from Maykop? Yes, perhaps, if this were true. However, it's not.

To be sure, Yamnaya does show a close genome-wide genetic relationship with an earlier group from the North Caucasus region: the so called Eneolithic steppe people. But they can't be linked to Maykop or even the roughly contemporaneous nearby Eneolithic Caucasus population, and seem to have vanished, at least as a coherent genetic unit, just as Maykop got going. Wang et al. managed to sequence three Eneolithic steppe samples with the following mtDNA haplogroups: H2, I3a and T2a1b.

H2 is too broad a haplogroup to bother with, but here are the results for I3a and T2a1b from the recently launched AmtDB, the first database of ancient human mitochondrial genomes (see here).

In a database of 1,131 ancient samples, I3a shows up in just five individuals, all of them associated with Yamnaya-related archeological cultures and populations: Poltavka (BARu), Unetice (UNC), Corded Ware (CWC), and Bell Beaker (BBC). Similarly, T2a1b shows up in just four individuals, all of them associated with Corded Ware (CWC) and Bell Beaker-derived Bronze Age Britons (BABI). And if I go back a step to T2a1, then the list reveals two Yamnaya individuals from what is now Kalmykia, Russia.

Thus, using just two mtDNA haplotypes I'm able to corroborate the results from genome-wide genetic data showing a close relationship between Eneolithic steppe and Yamnaya. So like I said, useful stuff.

This obviously begs the question: what does the AmtDB reveal about Maykop mtDNA haplotypes, especially in the context of the genetic relationship, or rather lack of, between Yamnaya and Maykop? Yep, again, the AmtDB basically corroborates the results from genome-wide genetic data.

But don't take my word for it. Stick the currently available Maykop mtDNA haplogroups into the AmtDB and see what happens (for your convenience I've made a list available here). Considering the close geographic and temporal proximity of Maykop to Yamnaya, you won't see an overly high sharing rate with Yamnaya and closely related populations. Moreover, Maykop shows several haplogroups that appear highly unusual in the context of the Eneolithic and Bronze Age steppe mtDNA gene pool, and, instead, link its maternal ancestry to those of the early European farmers, West Asians or even Central Asians, such as HV, M52, U1b, U7b and X2f.

See also...

Yamnaya: home-grown

Yamnaya isn't from Iran just like R1a isn't from India

Big deal of 2016: the territory of present-day Iran cannot be the Indo-European homeland

Best of 2008: Corded Ware DNA from Germany

One of the biggest hits of the year for this blogger was the discovery of Y-DNA haplogroup R1a among three Corded Ware skeletons from a burial site in Eulau, eastern Germany. It's an important result, because it links one of Europe's most dominant Y-haplogroups to a major Late Neolithic archeological complex.

All three individuals were confirmed to be paternally related via their shared Y-STR haplotype. Nevertheless, the outcome appears far from a random coincidence. Consider that in Europe today R1a shows its highest frequencies in Poland and Western Russia, which are both located in former Corded Ware territory, and where the Eulau R1a haplotype appears to have its closest modern matches. Moreover, the Corded Ware culture is often classified as an Indo-European culture by archeologists and linguists, while at the same time R1a has been posited as a marker of the early Indo-Europeans by some geneticists. Needless to say, I'm expecting R1a to be a common, and perhaps dominant marker among Corded Ware samples when more of them make it to the lab.

The consensus haplotype of the three individuals (based on most complete profile) gave two exact matches in in an European population sample of 11,213 haplotypes in a set of 100 populations (as of July 2008, Release ‘‘23’’ from 2008–01-15 14:44:25): one individual from Poland (1/939 from Gdansk) and one from Russia (1/48 from Tambov).

...

The Y haplotype was predicted using the Web-based program Haplotype Predictor (9). The three individuals of grave 99 belong to haplotype R1a, with a probability of 100% based on the Y-STR profile of individual 3 (10). To confirm haplogroup status, we further amplified an 85-bp fragment covering the Y-SNP marker SRY10831.2 characteristic for R1a (11). Primer sequences are given in Table S6. Sequences and sequenced clones from independent extract of all three individuals show the specific G to A transition identifying R1a (Fig. S5).

The mitochondrial DNA (mtDNA) lineages of the Eulau skeletons belonged to haplogroups K1b (3), X2 (2), H, I, K1a2, and U5b. Most of these maternal markers aren't particularly common in Europe today, and the overall result appears decidedly unusual compared to the mtDNA frequencies of modern European populations, largely because of the low frequency of H.

I'm quite certain this is at least partly due to the small sample size and presence of several related individuals skewing some of the frequencies. However, it's interesting to note that this pattern of discontinuity between mtDNA gene pools from different time periods has also been reported in other studies, some with larger samples, and focusing on different regions of Europe. So it might well be a signal of significant shifts in mtDNA frequencies during European prehistory and early history, possibly as a result of major migrations leading to significant population replacements.

Interestingly, one of the ancient K1b lineages most closely matched a haplotype shared by two modern Shugnans from Tajikistan. Exactly how the Corded Ware individual is related to these two Central Asians isn't clear yet, but Shugni is an Indo-Iranian language, so some kind of early Indo-European relationship is possible.

Citation...

Wolfgang Haak et al, Ancient DNA, Strontium isotopes, and osteological analyses shed light on social and kinship organization of the Later Stone Age, PNAS, Published online before print November 17, 2008, doi:10.1073/pnas.0807592105