Iron Age Tocharians of Yamnaya ancestry from Afanasevo show hg. R1b-M269 and Q1a1

New open access Ancient Genomes Reveal Yamnaya-Related Ancestry and a Potential Source of Indo-European Speakers in Iron Age Tianshan, by Ning et al. Current Biology (2019).

Interesting excerpts (emphasis mine, changes for clarity):

Here, we report the first genome-wide data of 10 ancient individuals from northeastern Xinjiang. They are dated to around 2,200 years ago and were found at the Iron Age Shirenzigou site. We find them to be already genetically admixed between Eastern and Western Eurasians. We also find that the majority of the East Eurasian ancestry in the Shirenzigou individuals is related to northeastern Asian populations, while the West Eurasian ancestry is best presented by ∼20% to 80% Yamnaya-like ancestry. Our data thus suggest a Western Eurasian steppe origin for at least part of the ancient Xinjiang population. Our findings furthermore support a Yamnaya-related origin for the now extinct Tocharian languages in the Tarim Basin, in southern Xinjiang.

Haplogroups

The dominant mtDNA lineages of the Shirenzigou people are commonly found in modern and ancient West Eurasian populations, such as U4, U5, and H, while they also have East Eurasian-specific haplogroups A, D4, and G3, preliminarily documenting admixed ancestry from eastern and western Eurasia.

The admixture profile is also shown on the paternal Y chromosome side that 4 out of 6 males in Shirenzigou (Figure S2) belong to the West Eurasian-specific haplogroup R1b (n = 2) and East Eurasian-specific haplogroup Q1a (n = 2), the former is predominant in ancient Yamnaya and nearly 100% in Afanasievo, different from the Middle and Late Bronze Age Steppe groups (Steppe_MLBA) such as Andronovo, [Potapovka], Srubnaya, and Sintashta whose Y chromosomal haplogroup is mainly R1a.

tocharians-y-dna-mtdna

Autosomal

We first carried out principal component analysis (PCA) to assess the genetic affinities of the ancient individuals qualitatively by projecting them onto present-day Eurasian variation (Figure 2). We observed a distinct separation between East and West Eurasians. Our ancient Shirenzigou samples and present-day populations from Central Asia and northwestern China form a genetic cline from East to West in the first PC. The distribution of Shirenzigou samples on the cline is relatively scattered with two major clusters, one being closer to modern-day Uygurs and Kazakhs and the other being closer to recently published ancient Saka and Huns from the Tianshan in Kazakhstan (…).

We applied a formal admixture test using f3 statistics in the form of f3 (Shirenzigou; X, Y) where X and Y are worldwide populations that might be the genetic sources for the Shirenzigou individuals. We observed the most significant signals of admixture in the Shirenzigou samples when using Yamnaya_Samara or Srubnaya as the West Eurasian source and some Northern Asians or Koreans as the East Eurasian source (Table S1). We also plotted the outgroup f3 statistics in the form of f3 (Mbuti; X, Anatolia_Neolithic) and f3 (Mbuti; X, Kostenki14) to visualize the allele sharing between population X and Anatolian farmers. As shown in Figure S3, the Steppe_MLBA populations including Srubnaya, Andronovo, and Sintashta were shifted toward farming populations compared with Yamnaya groups and the Shirenzigou samples. This observation is consistent with ADMIXTURE analysis that Steppe_MLBA populations have an Anatolian and European farmer-related component that Yamnaya groups and the Shirenzigou individuals do not seem to have. The analysis consistently suggested Yamnaya-related Steppe populations were the better source in modeling the West Eurasian ancestry in Shirenzigou.

tocharians-pca-admixture
PCA and ADMIXTURE for Shirenzigou Samples. Modified from the original to include in black squares samples related to Yamnaya.

Genetic Composition of Iron Age Shirenzigou Individuals

We continued to use qpAdm to estimate the admixture proportions in the Shirenzigou samples by using different pairs of source populations, such as Yamnaya_Samara, Afanasievo, Srubnaya, Andronovo, BMAC culture (Bustan_BA and Sappali_Tepe_BA) and Tianshan_Hun as the West Eurasian source and Han, Ulchi, Hezhen, Shamanka_EN as the East Eurasian source. In all cases, Yamnaya, Afanasievo, or Tianshan_Hun always provide the best model fit for the Shirenzigou individuals, while Srubnaya, Andronovo, Bustan_BA and Sappali_Tepe_BA only work in some cases. The Yamnaya_Samara or Afanasievo-related ancestry ranges from ∼20% to 80% in different Shirenzigou individuals, consistent with the scattered distribution on the East-West cline in the PCA

ancestry-tocharians

(…) we then modeled Shirenzigou as a three-way admixture of Yamnaya_Samara, Ulchi (or Hezhen) and Han to infer the source from the East Eurasia side that contributed to Shirenzigou. We found the Ulchi or Hezhen and Han-related ancestry had a complicated and unevenly distribution in the Shirenzigou samples. The most Shirenzigou individuals derived the majority of their East Eurasian ancestry from Ulchi or Hezhen-related populations, while the following two individuals M820 and M15-2 have more Han related than Ulchi/Hezhen-related ancestry.

One important question remains, though: how and when did these Proto-Tocharian speakers migrate from the Afanasevo culture in the Altai into the Tarim Basin? The traditional answer, now more likely than ever, is through the Chemurchek culture. See e.g. A re-analysis of the Qiemu’erqieke (Shamirshak) cemeteries, Xinjiang, China, by Jia and Betts JIES (2010) 38(4).

Also, given the apparent lack of (extra farmer ancestry that characterizes) Corded Ware ancestry, if the results were already suspicious before, how likely are now the published R1a(xZ93) and/or radiocarbon dates of the Xiaohe mummies from Li et al. (2010, 2015)? Because, after all, one should have expected in such a late date a generalized admixture with neighbouring Srubna/Andronovo-like populations.

Related

Yamna/Afanasevo elite males dominated by R1b-L23, Okunevo brings ancient Siberian/Asian population

afanasevo-okunevo

Open access paper New genetic evidence of affinities and discontinuities between bronze age Siberian populations, by Hollard et al., Am J Phys Anthropol. (2018) 00:1–11.

NOTE. This seems to be a peer-reviewed paper based on a more precise re-examination of the samples from Hollard’s PhD thesis, Peuplement du sud de la Sibérie et de l’Altaï à l’âge du Bronze : apport de la paléogénétique (2014).

Interesting excerpts:

Afanasevo and Yamna

The Afanasievo culture is the earliest known archaeological culture of southern Siberia, occupying the Minusinsk-Altai region during the Eneolithic era 3600/3300 BC to 2500 BC (Svyatko et al., 2009; Vadetskaya et al., 2014). Archeological data showed that the Afanasievo culture had strong affinities with the Yamnaya and pre-Yamnaya Eneolithic cultures in the West (Grushin et al., 2009). This suggests a Yamnaya migration into western Altai and into Afanasievo. Note that, in most current publications, “the Yamnaya culture” combines the so-called “classical Yamnaya culture” of the Early Bronze Age and archeological sites of the preceding Repin culture in the middle reaches of the Don and Volga rivers. In the present article we conventionally use the term Yamnaya in the same sense, in which case the beginning of the “Yamnaya culture” can be dated after the middle of the 4th millennium BC, when the Afanasievo culture appeared in the Altai.

Because of numerous traits attributed to early Indo-Europeans and cultural relations with Kurgan steppe cultures, members of the Afanasievo culture are believed to have been Indo-European speakers (Mallory and Mair, 2000). In a recent whole-genome sequencing study, Allentoft et al. (2015) concluded that Eastern Yamnaya individuals and Afanasievo individuals were genetically indistinguishable. Moreover, this study and one published concurrently by Haak et al. (2015) analyzed 11 Eastern Yamnaya males and showed that all of them belonged to the R1b1a1a (formerly R1b1a) (…)

indo-european-uralic-migrations-afanasevo
Early Chalcolithic migrations ca. 3300-2600 BC.

Published works indicate that R1b was a predominant haplogroup from the late Neolithic to the early Bronze Age, notably in the Bell Beaker and Yamnaya cultures (Allentoft et al., 2015; Haak et al., 2015; Lee et al., 2012; Mathieson et al., 2015). Nearly 100% of the Afanasievo men we typed belonged to the R1b1a1a subhaplogroup and, for at least three of them, more precisely to the L23 (xM412) subclade. (…)

(…) our results therefore support the hypothesis of a genetic link between Afanasievo and Yamnaya. This also suggests that R1b was indeed dominant in the early Bronze Age Siberian steppe, at least in individuals that were buried in kurgans (possibly an elite part of the population). The geographical and temporal distribution of subhaplogroup R1b1a1a supports the hypothesis of population expansion from West to East in the Eurasian steppe during this period. It should however be noted that the Yamnaya burials from which the samples for DNA analysis were obtained (Allentoft et al., 2015; Haak et al., 2015; Mathieson et al., 2015) were dated within the limits of the Afanasievo period. Ancestors of both East Yamnaya and Afanasievo populations must therefore be sought in the context of earlier Eneolithic cultures in Eastern Europe. Sufficient Y-chromosomal data from such Eneolithic populations is, unfortunately, not yet available.

mtdna-ydna-afanasevo-okunevo
Mitochondrial- (A) and Y- (B) haplogroup distribution in studied populations

Okunevo and paternal lineage shift in South Siberia

Results obtained in the current study, from more than a dozen Okunevo individuals belonging to the earliest stage of Okunevo culture, that is the Uibat period (2500–2200 BC) (Lazaretov, 1997), suggest a discontinuity in the genetic pool between Afanasievo and Okunevo cultures. Although Y-chromosomal data obtained for bearers of the Okunevo culture showed that one individual carried haplogroup R1b, most Okunevo Y-haplogroups are representative of an Asian component represented by paternal lineages Q and NO1.

Okunevo carrier of Y-haplogroup Q1b1a-L54, which also supports this hypothesis (L54 being a marker of the lineage from which M3, the main Ameridian lineage, arose). Okunevo people could therefore be a remnant paleo-Siberian population with possible Afanasievo input, as suggested by the presence of the R1b1a1a2a subhaplogroup in one individual.

indo-european-uralic-migrations-afanasevo-late
Late Chalcolithic migrations ca. 2600-2250 BC.

Replacement of Asian Indo-European elite lineages by R1a

Published genetic data from the late Bronze Age Andronovo culture from the Minusinsk Basin (Keyser et al., 2009), the Sintashta culture from Russia (Allentoft et al., 2015) and the Srubnaya culture from the region of Samara (Mathieson et al., 2015), show that males did not belong to Y-haplogroup R1b but mostly to R1a clades: there appears to have been a change in the dominant Y-chromosomal haplogroup between the early and the late Bronze Age in these regions. Moreover, as described in Allentoft et al. (2015), the Andronovo and Sintashta peoples were closely related to each other but clearly distinct from both Yamnaya and Afanasievo. Although these results do not imply that Y-haplogroup R1b was entirely absent in these later populations, they could correspond to a replacement of the elite between these two main periods and therefore a difference in the haplogroups of the men that were preferentially buried.

indo-european-uralic-migrations-okunevo-andronovo
Early Bronze Age migrations ca. 2250-1750 BC.

Afanasevo and the Tarim Basin

The discovery, in the Tarim Basin, of well-preserved mummies from the Bronze Age allows for the construction of two hypotheses regarding the peopling of the Xinjiang province at this period. The “steppe hypothesis,” argues for a link with nomadic steppe herders (Hemphill and Mallory, 2004), possibly represented in this case by Afanasievo populations and their descendants (Mallory and Mair, 2000). However, newly published cultural data from the burial grounds of Gumugou (Wang, 2014) and Xiaohe (Xinjiang, 2003, 2007) shows material culture and burial rites incompatible with the Afanasievo culture. The earliest 14C date for Tarim Basin burials would place them at the turn of the 2nd millenium BC (Wang, 2013), 500 years after the Afanasievo period.

Instead, early Gumugou and Xiaohe burial grounds were contemporary with the start of the Andronovo period. Likewise, the Bronze Age population of the Xinjiang at Gumugou/Qäwrighul is not phenotypically closest to Afanasievo but to the Andronovo (Fedorovo) group of northeastern Kazakhstan and western Altai (Kozintsev, 2009). Our investigations demonstrate that Y-chromosomal lineage composition is also compatible with the notion that the ancient Tarim population was genetically distinct from the Afanasievo population. The only Y-haplogroup found by Li et al. (2010) in the Bronze Age Tarim Basin population was Y-haplogroup R1a, which suggests a proximity of this population with Andronovo groups rather than Afanasievo groups.

I don’t think these finds are much of a surprise based on what we already know, or need much explanation…

I would add that, once again, we have more proof that the movement of Okunevo and related ancient Siberian migrants from Central or North Asia will not be able to explain the presence of Uralic languages spread over North-East Europe and Scandinavia already during the Bronze Age.

Also interesting is to read in more peer-reviewed papers the idea of Late Indo-European speakers clearly linked to the expansion of patrilineally-related elite males marked by haplogroup R1b-L23, most likely since Eneolithic Khvalynsk/Repin cultures.

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