mtDNA from Xiaohe cemetery

BMC Genetics 2015, 16:78 doi:10.1186/s12863-015-0237-5

Analysis of ancient human mitochondrial DNA from the Xiaohe cemetery: insights into prehistoric population movements in the Tarim Basin, China

Chunxiang Li et al.

Abstract

Background

The Tarim Basin in western China, known for its amazingly well-preserved mummies, has been for thousands of years an important crossroad between the eastern and western parts of Eurasia. Despite its key position in communications and migration, and highly diverse peoples, languages and cultures, its prehistory is poorly understood. To shed light on the origin of the populations of the Tarim Basin, we analysed mitochondrial DNA polymorphisms in human skeletal remains excavated from the Xiaohe cemetery, used by the local community between 4000 and 3500 years before present, and possibly representing some of the earliest settlers.

Results

Xiaohe people carried a wide variety of maternal lineages, including West Eurasian lineages H, K, U5, U7, U2e, T, R*, East Eurasian lineages B, C4, C5, D, G2a and Indian lineage M5.

Conclusion

Our results indicate that the people of the Tarim Basin had a diverse maternal ancestry, with origins in Europe, central/eastern Siberia and southern/western Asia. These findings, together with information on the cultural context of the Xiaohe cemetery, can be used to test contrasting hypotheses of route of settlement into the Tarim Basin.

Link

Ancient DNA from Di-qiang populations in the Xinjiang

American Journal of Physical Anthropology DOI: 10.1002/ajpa.22690

Ancient DNA reveals a migration of the ancient Di-qiang populations into Xinjiang as early as the early Bronze Age

Shi-Zhu Gao et al.

Xinjiang is at the crossroads between East and West Eurasia, and it harbors a relatively complex genetic history. In order to better understand the population movements and interactions in this region, mitochondrial and Y chromosome analyses on 40 ancient human remains from the Tianshanbeilu site in eastern Xinjiang were performed. Twenty-nine samples were successfully assigned to specific mtDNA haplogroups, including the west Eurasian maternal lineages of U and W and the east Eurasian maternal lineages of A, C, D, F, G, Z, M7, and M10. In the male samples, two Y chromosome haplogroups, C* and N1 (xN1a, N1c), were successfully assigned. Our mitochondrial and Y-chromosomal DNA analyses combined with the archaeological studies revealed that the Di-qiang populations from the Hexi Corridor had migrated to eastern Xinjiang and admixed with the Eurasian steppe populations in the early Bronze Age.

Link

AAPA 2012 abstracts (part 1)

Here are some interesting abstracts from the 81st Annual Meeting of the American Association of Physical Anthropologists.


Maternal marks of admixture in Cape Coloreds of South Africa.
KRISTINE G. BEATY1, DELISA L. PHILLIPS1, MACIEJ HENNEBERG2 and MICHAEL H. CRAWFORD1.

Previous studies of genetic diversity have suggested that the Cape Coloureds of South Africa are a highly admixed population with genetic roots from indigenous African groups including Khoisans, and the later arrival of Bantu speaking Xhosa farmers. Further genetic contributions came during European colonization of South Africa, which added to the inclusion of largely male European markers to the gene pool. Slaves from Indonesia, Malaysia, Madagascar and India are also thought to have contributed to the genetic makeup of this ethnic group. This study examines the maternal contribution of each of these groups to the genetic diversity of the Cape Coloreds through sequencing of the hypervariable region I of the mitochondrial DNA and through restriction fragment length polymorphism.
A total of 123 individuals were examined for this study. High frequencies of haplogroups L1 and L2 were found at 81.3 percent in this group (100 of the 123 individuals), which indicates that this group has a large African contribution to its mitochondrial makeup. Restrictions of the major European haplogroups identified nine individuals, 7.3 percent of the sample, belonged to haplogroups I and J. Five individuals (4.1 percent of the sample) belonged to the superhaplogroup M, indicating that Asian slaves did contribute to the maternal gene pool. The majority of maternal lineages in this Cape Coloured sample are African in origin, with some European influence and a small contribution from Asian maternal lineages.

Ancient DNA reveals the population origin of the Eastern Xinjiang.
SHIZHU GAO2, HONGJIE LI1, CHUNXIANG LI1 and HUI ZHOU1,3.

Connecting with the Turpan Basin, the Eurasia steppe and the Gansu Corridor, the Eastern region of Xinjiang has played a significant role in the history of human migration, cultural developments, and communications between the East and the West. The population origin, migration and integration of this region have attracted extensive interest among scientists.
In order to research the population origin and movement of the Eastern Xinjiang, genetic polymorphisms studies of the Hami population were conducted. The Hami site is located in the East of Tian-Moutain in Xinjiang, dating back to the Bronze-early Iron Age. Archaeological studies showed that the culture of the Hami site possessed features from both the East and the West. Ancient mtDNA analysis showed that A, C, D, F, G, Z and M7 of the Eastern maternal lines, and W, U2e, U4, and U5aof the Western maternal lines were identified. Tajimas’D test and mismatch distribution analysis show that the Hami population had experienced population expansion in recent time. The demographic analysis of haplogroups suggests that the populations of the Northwest China, Siberia and the Central Asia have contributed to the mtDNA gene pool of the Hami population.
Our study reveals the genetic structure of the early population in Eastern Xinjiang, and its relationships with other Eurasian populations. The results will provide valuable genetic information to further explore the population origin and migration of Xinjiang and Central Asia.

Analysis of Chuvash mtDNA points to Finno-Ugric origin.
ORION M. GRAF1, STEPHEN M. JOHNSON1, JOHN MITCHELL2, STEPHEN WILCOX3, GREGORY LIVSHITS4 and MICHAEL H. CRAWFORD1.

A sample of 92 unrelated individuals from Chuvashia, Russia was sequenced for hypervariable region-I (HVR-I) of the mtDNA molecule. These data have been verified using RFLP analysis of the control region, revealing that the majority exhibit haplogroups H (31%), U (22%), and K (11%), which occur in high frequencies in western and northern Europe, but are virtually absent in Altaic or Mongolian populations. Multidimensional scaling (MDS) was used to examine distances between the Chuvash and reference populations from the literature. Neutrality tests (Tajima’s D (-1.43365) p<0.05, Fu’s FS (-25.50518) p<0.001) and mismatch analysis, which illustrates unimodal distribution, all suggest an expanding population.
The Chuvash speak a Turkic language that is not mutually intelligible to other extant Turkish groups, and their genetics are distinct from Turkic-speaking Altaic groups. Some scholars have suggested that they are remnants of the Golden Horde, while others have advocated that they are the products of admixture between Turkic and Finno-Ugric speakers who came into contact during the 13th century. Earlier genetic research using autosomal DNA markers indicated a Finno-Ugric origin for the Chuvash. This study examines uniparental mitochondrial DNA markers to better elucidate their origins. Results from this study maintain that the Chuvash are not related to Altaic or Mongolian populations along their maternal line, thus supporting the “Elite” hypothesis that their language was imposed by a conquering group —leaving Chuvash mtDNA largely of Eurasian origin. Their maternal markers appear to most closely resemble Finno-Ugric speakers rather than Turkic speakers.

An ancient DNA perspective on the Iron Age “princely burials” from Baden-Wurttemberg, Germany.
ESTHER J. LEE1, CHRISTOPH STEFFEN1, MELANIE HARDER1, BEN KRAUSE-KYORA1, NICOLE VON WURMB-SCHWARK2 and ALMUT NEBEL3.

During the Iron Age in Europe, fundamental social principles such as age, gender, status, and kinship were thought to have played an important role in the social structure of Late Hallstatt and Early Latene societies. In order to address the question of kinship relations represented in the Iron Age “princely burials” that are characterized by their rich material culture, we carried out genetic analysis of individuals associated with the Late Hallstatt culture from Baden-Wurttemberg, Germany. Bone specimens of thirty-eight skeletal remains were collected from five sites including Asperg Grafenbuhl, Muhlacker Heidenwaldle, Hirschlanden, Ludwigsburg, and Schodeingen. Specimens were subjected to DNA extraction and amplification under strict criteria for ancient DNA analysis. We successfully obtained mitochondrial DNA (mtDNA) control region sequences from seventeen individuals that showed different haplotypes, which were assigned to nine haplogroups including haplogroups H, I, K, U5, U7, W, and X2b. Despite the lack of information from nuclear DNA to infer familial relations, information from the mtDNA suggests an intriguing genetic composition of the Late Hallstatt burials. In particular, twelve distinct haplotypes from Asperg Grafenbuhl suggest a heterogeneous composition of maternal lineages represented in the “princely burials”. The results from this study provide clues to the social structure reflected in the burial patterns of the Late Hallstatt culture and implications on the genetic landscape during the Iron Age in Europe.

Genetic snapshot from ancient nomads of Xinjiang.
HONGJIE LI1, SHIZHU GAO2, CHUNXIANG LI1, YE ZHANG1, WEN ZENG3, DONG WEI3 and HUI ZHOU1,3.

Nomads of the Eurasian steppes are known to have played an important role in the transfer commodities and culture among East Asia, Central Asia, and Europe. However, the organization of nomadic societies and initial population genetic composition of nomads were still poorly understood because of few archaeological materials and written history.
In this study, the genetic snapshot of nomads was emerged by examining mitochondrial DNA and Y-chromosome DNA of 30 human remains from Heigouliang (HGL) site in the eastern of Xinjiang, which dated 2000 years ago and associated to the nomadic culture by archaeological studies. Mitochondrial DNA analysis showed that the HGL population included both East Eurasian haplogroups (A, C, D, G, F and Z) and West Eurasian haplogroups (H, K, J, M5 and H). The component of Eastern haplogroups is dominant. The distribution frequency and Fst values of Eastern haplogroups indicated the HGL population presented close genetic affinity to the nearby region modern populations of Gansu and Qinghai, while those of western haplogroups showed similar with Mongolia and Siberia populations. The results implied various maternal lineages were introduced into the HGL population. Regarding the Y chromosomal DNA analysis, nearly all samples belonged to haplogroup Q which is thought to be the mark of the Northern Asian nomads. We identified paternal kinship among three individuals at the same tomb by Y-STR marker.
Combined with archaeological and anthropological investigations, we inferred that the gene flow from the neighboring regions was possibly associated with the expansion of Xiongnu Empire.

Vikings, merchants and pirates at the top of the world: Y-chromosomal signatures of recent and ancient migrations in the Faroe Islands.
ALLISON E. MANN1, EYDFINN MAGNUSSEN2 and CHRISTOPHER R. TILLQUIST1.

The Faroe Islands are a small archipelago in the North Atlantic Ocean. With a current population of approximately 48,000 individuals and evidence of high levels of genetic drift, the Faroese are thought to have remained highly homogeneous since the islands were settled by Vikings around 900CE. Despite their geographic isolation, however, there is historical evidence that the Faroese experienced sporadic contact with other populations since the time of founding. Contact with Barbary pirates in the seventeenth century is documented in the Faroes; there is also the possibility of modern migrations to work in the highly productive fishery. This study set out to distinguish the signal of the original founders from later migrants. Eleven Y-chromosomal STR markers were scored for 139 Faroese males from three geographically dispersed islands. Haplotypes were analyzed using Athey's method to infer haplogroup. Median-joining networks within haplogroups were constructed to determine the phylogenetic relationships within the Faroese and between likely parental populations—Danish, Irish, and Norwegians. Dispersal patterns of individuals around Faroese haplogroups suggest different times of haplotype introduction to the islands. The most common haplogroup, R1a, consists of a large node with a tight network of neighbor haplotypes, such that 68% of individuals are one or two mutational steps away. This pattern may represent the early founder event of R1a in the Faroes. Other distributions, especially of non-Scandinavian haplotypes, document more recent introductions to the islands. The overall pattern is one of a strong founder effect followed by minor instances of later migrations.

Date estimates for major mitochondrial haplogroups in Yemen.
DEVEN N. VYAS1, VIKTOR ČERNÝ2, ALI AL-MEERI3 and CONNIE J. MULLIGAN1.

Yemen occupies a key location as the first stop for anatomically modern humans on a theoretical southern migration route out of Africa. If modern humans did pass through Yemen during the first migrations out of Africa and if they left modern-day descendants, we would expect to see deep divergences in the Yemeni mitochondrial gene tree. Alternatively, if modern humans passed through Yemen but did not leave modern-day descendants or if Yemen was not on the path of these ancient migrations, we would expect more recent dates to be associated with Yemeni mitochondrial haplogroups.
Using 44 previously sequenced mitochondrial genomes as well as 24 newly sequenced mitochondrial genomes from samples collected throughout Yemen, several methods were used to estimate divergence dates of major Yemeni haplogroups including L2, M, R0a and HV. Specifically, phylogenetic trees were generated using MrBayes and maximum likelihood methods. Bayesian and ρ statistic based methods were used to estimate dates of Yemeni haplogroups and these dates were compared with each other, previously published dates for these haplogroups, approximate dates of climatic change that might be expected to correlate with population expansions, and estimates based on archaeological and paleontological evidence for the first migrations out of Africa. These comparisons are intended to cover the range of possible haplogroup divergence dates with respect to the history of early modern humans in southern Arabia.

On Tocharian origins

Where did the Tocharians originate from? J.P. Mallory's recent talk has been somewhat of an eye-opener for me, as Prof. Mallory brought to my attention two important issues:

1. The lack of a clear connection between Afanasyevo and the Tarim Basin.
2. The existence (in Tocharian) of a rich agricultural IE terminology related to cereals, as well as the domesticated pig, which cannot be easily explained if Tocharians arrived in Xinjiang from the steppes to the north, and, ultimately from eastern Europe.

To begin with, I want to point out an important issue: we cannot assume that the earliest Caucasoids of Xinjiang, including some of the famous early Tarim mummies were Tocharian speaking. There are several arguments why this is so:

1. Tocharian is first attested in the 8th c. AD, that is, about 3 thousand years after the earliest detected Caucasoids in the region
2. There has been a shift in the region from Tocharian and eastern Iranian languages to Turkic over the last thousand years or so. Why assume linguistic continuity in the preceding three thousand?
3. Indeed, there has been linguistic shift throughout other regions of Eurasia in shorter timespans, such as the spread of Slavic across most of eastern Europe, the virtual extinction of Celtic in most of western Europe, the replacement of multiple languages by Arabic in the Near East, and so on. Linguistic continuity does not seem to be an appropriate default position in the absence of direct evidence.
4. The earliest Caucasoids of the Tarim were already substantially mixed with Mongoloids at least in their mtDNA. This reduces our confidence that they spoke an Indo-European language, as there is a pattern of Caucasoid patrilineages combined with Mongoloid mtDNA in present-day non-IE South Siberians
5. Indeed, the current Turkic Uyghurs, who are closer (temporally) to the Tocharians than the early Bronze Age Caucasoids have a rich assortment of Caucasoid Y-chromosome haplogroups, whereas the early Bronze Age ones seem to have belonged uniformly to R1a1. What languages were spoken by the non-R1a1 Caucasoids who arrived in the Tarim prior to the Turkification of the region?

To summarize the first part of the argument: the early population of the Tarim does not have clear steppe connections, it may not have been Indo-European speaking, and even if it were, it did not necessarily speak the same language as the later Tocharians. Moreover, the Tocharian language has a vocabulary without clear steppe associations, but with rich agricultural ones.

In search of the Tocharians

We may discover the origin of the Tocharians by a careful sorting of Y-chromosome lineages in the present-day Uyghur population of Xinjiang that is assumed to have absorbed the pre-Turkic inhabitants of the region:

1. Remove all east Eurasian lineages that are likely to be associated with the Xiongnu, Mongols, or Uyghur
2. Remove all west Eurasian lineages that can be explained from a non-Tocharian source (such as Iranians, or various Silk Road outliers)
3. See if anything is left

A recent paper by Zhong et al. provides rich data on Uyghurs that can be used to carry out this program.

The phylogeographic analysis of these lineages does leave some candidates:

1. Haplogroup D can be excluded as Mongolian/Tibetan
2. Haplogroup E can be excluded as Mediterranean/African
3. Haplogroup C can be excluded as Altaic/South Asian (C5)
4. Haplogroup G2a* (West Asian) does not seem to have an important presence (3 samples)
5. Haplogroup H can be excluded as South Asian
6. Haplogroup I can be excluded as a European outlier (1 sample)
7. Haplogroup J*(xJ2) can be excluded as NE Caucasian/Semitic with small presence (2 samples)
8. Haplogroup NO; haplogroup N has been founded in a Xiongnu context, so it is likely intrusive; O is East Eurasian
9. Haplogroup Q is also associated with Xiongnu nomads from Pengyang

This analysis leaves four candidates: J2-M172, R1a1a-M17, R1b-M343, and L-M20.

We can exclude L-M20 because its overall low frequency in most populations makes it difficult, at present, to make a definitive pronouncement on its origin, except perhaps for its Indian L1 clade which is absent here.

J2, present in both its J2a and J2b subclades here at substantial frequencies has an origin in West Asia, as well as a substantial presence among Indo-Iranian speakers. While it is possible (indeed likely, in my opinion) to have been present among the Tocharians, we cannot exclude the possibility that it represents either a specifically Iranian influence, or even something earlier than both.

R1a1a is present in both the steppe, as well as South Asia and West Asia. Its high frequency among some Indo-Iranian populations also makes it difficult to ascribe a specifically Tocharian origin to it.

This leaves only R1b-M343 as a candidate. Have we found a genuine Tocharian genetic signature?

The West Asian roots of R-M343 (?)

R-M343 and its main R-M269 clade are in a sense exasperating: the combination of their widespread distribution from Africa, the Atlantic, to the depths of Inner Asia, combined with their apparent Y-STR-estimated youth make it nearly impossible to associate them with a specific archaeological or historical phenomenon.

Where could R-M269 have come from? It was not present, as far as we can tell, in early Bronze Age Xinjiang, and neither has it been detected in south Siberians. The steppe/"northern" route seems out.

A southern route, from the Indian subcontinent also seems out, as despite its ubiquity elsewhere in Eurasia, it seems to have (mostly) skipped both India and (to an extent) Pakistan.

An indigenous origin seems highly unparsimonious, as it would require that it trek all the way to the Atlantic, but make hardly an impact in either East Asia or South Asia.

As far as I can tell, the only explanation for the presence of R-M343 in Xinjiang is West Asia, or at least Central Asia west of the Tarim. There it can be found at a high frequency in Armenians, Turks, north Iranians, and Lezgins among others. And, unlike both J2 and R1a1a, R-M343 does not seem to be Indo-Iranian (due to its absence in India).

Gamkrelidze and Ivanov cited W. N. Henning to the effect that the ancestors of the Tocharians could be identified with the Gutians from the Zagros, a people that attacked the Sumerians and founded a dynasty. As usual, I don't presume to know the linguistic evidence for this, but this hypothesis would place the ancestors of the Tocharians in the "right spot": virtually all of their Caucasoid Y-chromosome gene pool could be explained with an origin in north Iran.

A model of Tocharian origins

The model of Tocharian origins I present is simplicity itself:

First, Tocharians are descended from a group of farmers that moved east of the PIE homeland and settled on the Zagros and beyond, south of the Caspian sea.

Second, their trek to the Tarim was a simple west-to-east movement along what would later become the Silk Road, beyond the Taklamakan desert and into the Tarim basin. There they must've mixed with the early pre-IE mixed Caucasoid/Mongoloid population of the early Bronze Age. The desert probably sheltered them, to an extent, from encroachments by the Iranians.

An open question remains: were the Tocharians late fugitives who were pushed out of their ancestral homelands by the emergence of the Iranians and entered the Tarim late? Or were they established there fairly early and were the historical Tocharians are the eastern relics of a once great people that was not Iranized unlike most of the people of Central Asia?

Autosomal evidence

The fine-scale analysis of the Dodecad project on a sample of 10 Uyghurs provides some additional evidence:

The Uyghurs seem to lack the Southwest Asian component that is ubuiquitous in most of West Asia today, and may have, in large part, expanded with the more recent spread of Semitic languages. They are similar, in that respect with South Asians, suggesting that neither the spread of Islam to the east nor the cosmopolitanism of the Silk Road were enough to bring this component to the region. Hence, the plethora of Caucasoid Y-haplogroups in the region cannot be attributed to recent arrivals.

The absence of specific South European components in them also suggests that the opinion of some linguists and archaeologists that would see the Tocharians related to Celts and moving from deep within Europe, or even Western Europe to the Tarim, are unlikely; the south European component is ubuiquitous in Europe, and the Uyghurs, like South Asians, seem to lack it entirely.

Their Caucasoid components are primarily West Asian and North European. Projecting them on the East Eurasian/West Asian/North European PCA plot (left), it is clear that they are more West Asian than North European, a result that is in agreement with their ADMIXTURE results.

Notice also how the North European/West Asian ratio is reversed for the more northern-latitude Uralic/Altaic speakers (Selkups, Dolgans, etc.).

Of course, the results should be interpreted with caution, but they seem perfectly in agreement with the model presented here:

• the Uyghurs are partly Mongoloid both because they may carry the legacy of the ancient mixed population of the Tarim, and also because of their more recent Turkic/Xiongnu associations.
• with respect to their Caucasoid components, they are mainly West Asian (with the West Asian component also being primary in South Asia), but somewhat shifted to the north due to their absorption of mixed Northern Caucasoid/Mongoloid peoples from the steppelands.

Conclusion

The mystery of the Tocharians may be that there is no mystery. The Tocharians are revealed to have been just another West Asian branch of the Indo-European family that, unlike most of its cousins, went east, absorbed Northern Caucasoid, Mongoloid, and South Asian population elements, emerged long enough in history to leave us a written record of their presence, before succumbing to the Xiongnu and the Mongols.

Thankfully, by combining the remnants of their language, and fragments of their DNA in their descendants, we are able to reconstruct the history of this, once forgotten people

Before Silk: Unsolved Mysteries of the Silk Road by Colin Renfrew

A great talk by Colin Renfrew at the Penn Museum, a must view for anyone interested in Eurasian prehistory. It's good to know that Renfrew holds that the Tocharians originated in West Asia and spread along the Silk Road (south of the Caspian) and not along the steppes. That is also my opinion, and I would perhaps associate them with the J2a/R1b-rich population of eastern Anatolia, Trascaucasia and North Iran, and, perhaps, even related to the Gutians from the Zagros (after Gamkrelidze and Ivanov). That would explain quite well, I believe the anomaly that is the high J2a/R1b frequency in the region.

Also, I would disagree with long-term persistence of Tocharian in Xingiang; it's more likely that this was due to a late migration from somewhere to the west that was eventually swamped by the much more successful wave of the Indo-Iranians that must've involved a J2a/G2a/R1a1 combination. I've made the point before that the vast majority of the territory of Europe and West Asia has shifted language (if not language family) over a span of 2-3 thousand years, so I see no real reason to imagine 2-3 thousand years of linguistic continuity in Xinjiang until the 8th c. AD when Tocharian is first attested.

UPDATE:

Here are various abstracts from the Symposium Reconfiguring the Silk Road: New Research on East-West Exchange in Antiquity; hopefully more videos will be uploaded.

UPDATE II:

James Mallory's talk is also uploaded:



He spends a great deal of his time establishing the (not controversial) idea that Tripolye cultures cannot explain the Yamna phenomenon east of the Dnieper. I will not argue with this, but it is rather a defensive stance of arguing against the spread of Indo-Europeans from the Balkans to the steppe-lands. Positive evidence for the spread of Yamna in the opposite direction is what is needed for the steppe model, and that is what is lacking: with the exception of some clearly Yamna-derived sites in the northern Balkans and Hungary, the links to the rest of the European Indo-Europeans are weak to non-existent.

Moreover, I would argue that the assumption that 3-4,000 years BC there were Indo-European speakers east of the Dnieper is itself suspect. There is no great necessity of explaining how Yamna was Indo-Europeanized from the Balkans, because there is no evidence that it was Indo-European. The first clearly attested Indo-European groups in the European steppe are the Scythians, and they appear in the 1st millennium BC, with both craniology and ancient sources agreeing that they were of eastern origin. So, the inability of the Balkan Tripolye Indo-Europeans of Indo-Europeanizing the Pontic steppe east of the Dnieper is really a non-sequitur, since one must first demonstrate that populations east of the Dnieper spoke Indo-European languages 3,000 years before a single branch of IE (the Iranic) appears in the region from the east.

Mallory also highlights some other substantial problems of the steppe model. Tocharian has IE words for cereals and pigs, and the evidence such as it is suggests that east of the Dnieper there were no domesticated cereals and no evidence of pigs. All this, of course, disappears once we accept that the Tocharians did not move across the steppe lands north of the Caspian, but south of it, from Iran and ultimately the Near East.

Mallory also points out that while he suspects Afanasievo to be linked to the Proto-Tocharians, the sum total of the evidence linking Xinjiang with Afanasievo is meagre. I would also add that, as I've explained above, if one were to establish links between Bronze Age Tarim and Afanasievo, that still leaves a couple of millennia until the first attestation of the Tocharian languages.

Another point of interest is the claim that Indo-Iranians and Tocharians must've been separated in space and time to evolve into so distinctive languages. But, that too is a non-sequitur. We only have to look at the Near East or the Caucasus to witness the co-existence of a handful of language families and dozens of distinct languages. You don't need a large separation to create a new language subfamily, but only a few rivers or high mountains, and Transcaucasia provides both in abundance. I would see Tocharians as the last remnant of the eastern Indo-Europeans, perhaps refugees from further west into Xinjiang itself, with Indo-Iranians pushing them eastward. As for the later steppe cultures that were unquestionably Iranic, these were probably formed after the collapse of the BMAC which sent off Indo-Aryan offshoots south in the 2nd millennium BC, and Iranic ones north, east, and west soon thereafter.

"Secrets of the Silk Road" @ Penn Museum

Here is the website of an exhibition that will run through March 28. There is also a weekly lecture series to accompany the event, the first few of which have been posted at the site. Here is the first one:

Introduction to the Silk Road by Nancy Steinhardt

The Tarim Basin Mummies by Victor Mair

UPDATE: Mair is mistaken when he states that Tocharian is the 2nd oldest language after Hittite.

Related:

• Y chromosomes and mtDNA in Bronze Age Tarim basin
• mtDNA evidence for Caucasoid-Mongoloid admixture in Xinjiang 2,500 years ago
• Mitochondrial DNA analysis of ancient Sampula population in Xinjiang

Y chromosomes and mtDNA in Bronze Age Tarim basin

This appears to be a published study by the same team which appeared in a recent National Geographic documentary on the Tarim mummies. The site of Xiaohe (of the current study) is earlier and to the southeast of Urumqi.

The finding that the Bronze Age population, like that of Krasnoyarsk Siberians belonged exclusively -as far as sampling allows- to Y-chromosome haplogroup R1a1 is extremely interesting as it raises the issue of when and how exactly the diverse extant Y-chromosome gene pool of Central Asia came about.

We can now confidently say that even at the early age of ~4ky BP an R1a1-bearing population of presumably western Eurasian origin had acquired a mixed mtDNA gene pool consisting of both west- and east-Eurasian mtDNA, which agrees with what was presented in the aforementioned documentary, in which many of the seemingly Caucasoid mummies had East Eurasian mtDNA.

From the paper:

The dominant haplogroup in the Xiaohe people was the East Eurasian lineage C, shared by 14 Xiaohe individuals who were associated with two different mtDNAhaplotypes (S1 and S2). According to the coding region 11969 A to G, all lineage C found in the Xiaohe people were further classified to subhaplogroup C4, which had D-loop group-specific polymorphisms at nucleotide positions (np) 16298 (T to C) and16327 (C to T) [18].

...

Besides the East Eurasian lineage, two West Eurasian mtDNA haplogroups H and K were found among the Xiaohe people. H lineage is the most common mtDNAhaplogroup in West Eurasia [20], but haplogroup H with a 16260T was shared by only nine modern people in Genbank, including one Italian, one German, one Hungarian,one Portuguese, one Icelander and four English people. Haplogroup K, a western Eurasian–specific haplogroup, is mainly distributed in Europe, central Asia, and Iran [20, 21]. However, haplogroup K with 16134T, found in the Xiaohe people, has not been found in modern people to our knowledge.

...

Among the Xiaohe people, three sequences with the unique HVRI motif 16189–16192–16311 formed a subcluster (Figure 2) and were not shared by modern people. [...] The results showed that they are related neither to the West Eurasian haplogroups UK, TJ, HV, R11and R1, nor to the East Eurasian haplogroups B and F. So we designated them as haplogroup R*temporarily. Another sequence with motif 16223–16304, shared by some people fromEast Asia, India, and Europe, was assigned to haplogroup M*.

The mtDNA results are interesting because they tie in with my theory of a boreal mtDNA-U zone which has recently found further support (and extended in time) with the mtDNA testing of Kostenki. Like the Krasnoyarsk Siberians the Caucasoid component in Xiaohe is light on U. Unfortunately, we don't have enough information to place the origin of this component in a particular region of West Eurasia.

A graphical display of this theory can be seen in Figure 5 from the paper (left). Sites 8, 9 and 3 (Lake Baikal and Xiognu) only have U5 "western" mtDNA, and, as I have argued in my previous post, represent the eastern edge of the "boreal zone" to which were added non-U bearing Caucasoids from the west.

As for the Y-chromosome results:

The Y chromosome haplogroup of the sevenmales were all assigned to haplogroup R1a1a through screening the Y-SNPs at M89,M9, M45, M173 and M198 successively. Haplogroup R1a1a is widely distributed inEurasia: it is mainly found in Eastern Europe, Central Asia, South Asia, Siberia,ancient Siberia, but rare in East Asia [22-24].

The authors address the origins of the admixture:

Given the unique genetic haplotypes and the particular archaeological culture, the

time of this admixture could be much earlier than the time at which the Xiaohe people were living at the site. This means that the time of their mingling was at least a 1000 years earlier than previously proposed.

...

The admixture therefore

probably occurred elsewhere, before immigration into the Tarim Basin. The Xiaohe

people might well have been an admixture at the time of their arrival. Where did the

initial admixture occur?

To answer that question, the authors identify Afanasievo and other steppe cultures as related to the Xiaohe people. This is not very surprising as the Afanasievo people were described in the anthropological literature as prominent-nosed Caucasoids of western origin, although individual skulls show Mongoloid influences.

So, it's possible that the admixture took place in Siberia, and an already admixed population found its way to Xiaohe by ~4ky BP. The important question is: what happened to the male lineages of the eastern component of this population?

Years ago, I advanced a "pendulum" theory of migrations in Eurasia to explain the fact that quite often we find in the northern belt from Europe to China populations with typically Western/Eastern Y-haplogroups accompanied by the "opposite" (Eastern/Western) mtDNA.

According to my thinking, this is due to the patriarchal nature of mobile Eurasian societies (whether nomads or hunters) in which the "clan" maintains its Y-chromosome gene pool but incorporates foreign females. Thus, the absence of non-R1a1 chromosomes can be explained by the fact that non-R1a1 male individuals were not incorporated into the "western" tribe that made its way across Eurasia from Europe to China, but Eastern Eurasian-mtDNA bearing females were gradually absorbed; such would have been plentiful among the indigenous Mongoloid populations that lived east of the Urals since the Paleolithic.

Thus, at the eastern end of this migration, we ended up with an R1a1-pure/East Eurasian mtDNA-heavy population.

Years later, the pendulum of Eurasian migration swung backwards, with some of the Asian R1a1-bearing individuals returning towards Europe (starting with the Scythians) to meet their distant cousins, this time shedding whatever east Eurasian mtDNA gene pool they had acquired, for the regular west Eurasian mtDNA gene pool that would have been reinforced in the return journey.

BMC Biology doi:10.1186/1741-7007-8-15

Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age

Chunxiang L et al.

Abstract

Background
The Tarim Basin, located on the ancient Silk Road, played a very important role in the history of human migration and cultural communications between the West and the East. However, both the exact period at which the relevant events occurred and the origins of the people in the area remain very obscure. In this paper, we present data from the analyses of both Y chromosomal and mitochondrial DNA (mtDNA) derived from human remains excavated from the Xiaohe cemetery, the oldest archeological site with human remains discovered in the Tarim Basin thus far.

Results
Mitochondrial DNA analysis showed that the Xiaohe people carried both the East Eurasian haplogroup (C) and the West Eurasian haplogroups (H and K), whereas Y chromosomal DNA analysis revealed only the West Eurasian haplogroup R1a1a in the male individuals.

Conclusion
Our results demonstrated that the Xiaohe people were an admixture from populations originating from both the West and the East, implying that the Tarim Basin had been occupied by an admixed population since the early Bronze Age. To our knowledge, this is the earliest genetic evidence of an admixed population settled in the Tarim Basin.

Link

Caucasoid mtDNA U3 and X2 in Taklamakan Desert

Related:

• Some mtDNA links between Europe and Asia
• Ancient mtDNA from Sampula population in Xinjiang
• mtDNA evidence for Caucasoid-Mongoloid admixture in Xinjiang 2,500 years ago
• mtDNA from Xinjiang

American Journal of Physical Anthropology doi:10.1002/ajpa.21257

Early Eurasian migration traces in the Tarim Basin revealed by mtDNA polymorphisms

Yinqiu Cui et al.

Abstract

The mitochondrial DNA (mtDNA) polymorphisms of 58 samples from the Daheyan village located in the central Taklamakan Desert of the Tarim Basin were determined in this study. Among the 58 samples, 29 haplotypes belonging to 18 different haplogroups were analyzed. Almost all the mtDNAs belong to a subset of either the defined Western or Eastern Eurasian pool. Extensive Eastern Eurasian lineages exist in the Daheyan population in which Northern-prevalent haplogroups present higher frequencies. In the limited existing Western Eurasian lineages, two sub-haplogroups, U3 and X2, that are rare in Central Asia were found in this study, which may be indicative of the remnants of an early immigrant population from the Near East and Caucasus regions preserved only in the Tarim Basin. The presence of U3 in modern and archeological samples in the Tarim Basin suggests that the immigration took place earlier than 2,000 years ago and points to human continuity in this area, with at least one Western lineage originating from the Near East and Caucasus regions.

Link

mtDNA evidence for Caucasoid-Mongoloid admixture in Xinjiang 2,500 years ago

Related:

• Ancient mtDNA from Sampula population in Xinjiang
• mtDNA of Tarim mummies

American Journal of Physical Anthropology doi:10.1002/ajpa.21237

Prehistorical East-West admixture of maternal lineages in a 2,500-year-old population in Xinjiang

Fan Zhang et al.

Abstract

As an area of contact between Asia and Europe, Central Asia witnessed a scenario of complex cultural developments, extensive migratory movements, and biological admixture between West and East Eurasians. However, the detanglement of this complexity of diversity requires an understanding of prehistoric contacts of the people from the West and the East on the Eurasia continent. We demonstrated the presence of genetic admixture of West and East in a population of 35 inhabitants excavated in Gavaerk in southern Xinjiang and dated 2,800-2,100 years before present by analyzing their mitochondrial DNA variations. This result indicates that the initial contact of the East and the West Eurasians occurred further east than Central Asia as early as 2,500 years ago.

Link

mtDNA of Tarim mummies

The National Geographic documentary on the Tarim mummies reports on recent mtDNA work on the Tarim mummies. The program doesn't really reveal anything new to anyone familiar with the story of these mummies, but there are some nice segments of some of them as they would have been during their lifetime. At some point, the camera shows what appear to be haplogroup assignments, although I wouldn't vouch as to what these actually mean. or to who exactly they belong. What they do say is that they found markers from "Europe, West Eurasia, Siberia, Tibet, Mongolia, even India". They also mention that the "Beauty of Loulan", the "Boy" have "unexpected marks of East Asian ancestry", and "Cherchen Man" also carries "a surprising East Asian lineage" and that the "Shaman" has a "lineage frequently seen in the Himalayas and India".

Ancient mtDNA from Sampula population in Xinjiang

From the paper:

Physical anthropology of Shao et al. revealed that the ancient human bones from Sampula exhibited primarily Mongoloid characteristics with certain European features, but Han et al. believed that Sampula populations are mainly of European character and actually are close to that of the Eastern Mediterranean type.

...

In conclusion, the analysis of mtDNA haplogroup distribution showed that the ancient Sampula was a complex population of European and Asian, corresponding to the physical anthopology result of Shao et al.

Progress in Natural Science, Volume 17, Issue 8 August 2007 , pages 927 - 933

Mitochondrial DNA analysis of ancient Sampula population in Xinjiang

Chengzhi Xie et al.

Abstract

The archaeological site fo Sampula cemetery was located about 14 km to the southwest of the Luo County in Xinjiang Khotan, China, belonging to the ancient Yutian kingdom. 14C analysis showed that this cemetery was used from 217 B.C. to 283 A. D. Ancient DNA was analysed by 364 bp of the mitochondrial DNA hypervariable region 1 (mtDNA HVR-1), and by six restriction fragment length polymorphism (RFLP) sites of mtDNA coding region. We successfully extracted and sequenced intact stretches of maternally inherited mtDNA from 13 out of 16 ancient Sampula samples. The analysis of mtDNA haplogroup distribution showed that the ancient Sampula was a complex population with both European and Asian Characteristics. Median joining network of U3 sub-haplogroup and multi-dimensional scaling analysis all showed that the ancient Sampula had maternal relationship with Ossetian and Iranian.

Link

Origins of the Uighur

Interesting bit from the paper:

Notably, the distribution of admixture proportions among UIG individuals is relatively even, with 48.7% the lowest admixture from European ancestry and the highest 62.2%. The standard deviation is only 3.8%, which is much smaller than the estimation for the African-American (AfA) population,58 suggesting a much longer history of admixture events for the Uyghur population compared with the AfA population.

The American Journal of Human Genetics, doi:10.1016/j.ajhg.2008.01.017

Analysis of Genomic Admixture in Uyghur and Its Implication in Mapping Strategy

Shuhua Xu et al.

Abstract

The Uyghur (UIG) population, settled in Xinjiang, China, is a population presenting a typical admixture of Eastern and Western anthropometric traits. We dissected its genomic structure at population level, individual level, and chromosome level by using 20,177 SNPs spanning nearly the entire chromosome 21. Our results showed that UIG was formed by two-way admixture, with 60% European ancestry and 40% East Asian ancestry. Overall linkage disequilibrium (LD) in UIG was similar to that in its parental populations represented in East Asia and Europe with regard to common alleles, and UIG manifested elevation of LD only within 500 kb and at a level of 0.1 < style="font-weight: bold;">we estimated that the admixture event of UIG occurred about 126 [107∼146] generations ago, or 2520 [2140∼2920] years ago assuming 20 years per generation. In spite of the long history and short LD of Uyghur compared with recent admixture populations such as the African-American population, we suggest that mapping by admixture LD (MALD) is still applicable in the Uyghur population but ∼10-fold AIMs are necessary for a whole-genome scan.

Link

"Celts" in Xinjiang

PhDiva criticizes a despicable Independent article titled "A meeting of civilisations: The mystery of China's celtic mummies". As I noted in a discussion list:

There is no evidence that the Urumqi mummies spoke Celtic languages, or that they were Europeans, or even Indo-Europeans. The DNA evidence can only be used to show that they were of West Eurasian, not European origin. As for their language, none of them have been accompanied, as far as I know, by any writings. It is reasonable that they might have spoken an Indo-European language, although by no means proven.

It is a sad state of affairs that editors allow such misleading information to be published.

One of the many idiotic statements in the article:

The Loulan Beauty, for example, was claimed by the Uighurs as their symbol in song and image, although genetic testing now shows that she was in fact European.

The "Loulan Beauty" may be one of the ancestors of the Uighurs, and she certainly belongs to the archaeological heritage of the region. Thus, it is reasonable and understandable that she will be made a symbol by the current inhabitants, however tenuous the connection.

Even the Slavs of Bulgaria identify with the ancient Thracians, the Turks identify with the Hittites and other extinct Anatolians, the Arabs of Egypt identify with the Egyptians, and the modern Germanic-speaking Britons identify with the "Celts". Such sentiments are understandable, albeit naive.

What is not excusable is to excise a part of Central Asian history and claim that it belongs to Europeans, or even more absurdly to Celts. However, we should perhaps excuse the journalist for his misstep, since he lives in a country where even professional geneticists have consistently oversold their research to a credulous public ready to swallow up stories about "Viking", "Celtic", or "Pictish" origins.

DNA testing of Xinjiang mummies

Genetic testing reveals awkward truth about Xinjiang’s famous mummies

“I spent six months in Sweden last year doing nothing but genetic research,” Mair said from his home in the United States where he teaches at the University of Pennsylvania.

“My research has shown that in the second millennium BC, the oldest mummies, like the Loulan Beauty, were the earliest settlers in the Tarim Basin.

“From the evidence available, we have found that during the first 1,000 years after the Loulan Beauty, the only settlers in the Tarim Basin were Caucasoid.”

East Asian peoples only began showing up in the eastern portions of the Tarim Basin about 3,000 years ago, Mair said, while the Uighur peoples arrived after the collapse of the Orkon Uighur Kingdom, largely based in modern day Mongolia, around the year 842.

“Modern DNA and ancient DNA show that Uighurs, Kazaks, Krygyzs, the peoples of Central Asia are all mixed Caucasian and East Asian. The modern and ancient DNA tell the same story,” he said.

Mair hopes to publish his new findings in the coming months.

China has only allowed the genetic studies in the last few years, with a 2004 study carried out by Jilin University also finding that the mummies’ DNA had Europoid genes, further proving that the earliest settlers of Western China were not East Asians.

See also this 2004 study on ancient Central Asians from Kazakhstan which essentially agrees with the content of this story, and a paper on a modern Caucasoid-Mongoloid population from Xinjiang.

The Sand Dune Forgotten by Time

Archaeologists working in the extreme desert terrain of the Xinjiang Uygur Autonomous Region have moved a step closer to unraveling the mystery of a 40-century-old civilization.

They unearthed 163 tombs containing mummies during their ongoing and long excavation at the mysterious Xiaohe tomb complex.



And it's all thanks to the translation of a diary kept by a Swedish explorer more than 70 years ago.

"We have found more than 30 coffins containing mummies," said Idelisi Abuduresule, head of the Xinjiang Cultural Relics and Archaeology Institute and the excavation team.

The complex is believed to contain 330 or so tombs buried in several layers within a 2,500-square-meter sand dune.

"Most of the items are in the original state of the time when they were buried, and that will help reveal a lot of information about the society and life style of the people of that time," said Idelisi, during his trip back from the desert dust and heat to the autonomous region's capital Urumqi to record the finds, and store the artifacts.

The Xiaohe tombs are believed to have been the burial site of the mysterious Loulan Kingdom, which disappeared without historical trace about 15 centuries ago.

Today's archaeologists are following in the footsteps of Swedish explorer Folke Bergman, who in 1934 ventured south along a river in Lop Nur Desert in the eastern part of Xinjiang.

He said on his return that he'd discovered a dune harboring over 1,000 coffins that date back 4,000 years ago.

He named the place Xiaohe (small river) tombs.

But the river he used to navigate to this ancient site dried up and the dune and its tombs were forgotten about for decades.

In the late 1990s, however, Chinese sociologists translated Bergman's records on archaeological exploration in the area into Chinese and the hunt for dune and its mysteries was once again underway.

In addition to burial articles such as bent wooden blocks and straw baskets, Idelisi's team has found in some coffins wooden figures wrapped in leather instead of mummified bodies.

A bird's-eye view of Xiaohe tombs shows the oval-shape dune taking on the appearance of dumpling pricked full of chopsticks.

Above every coffin protrudes two thick wooden stakes, a symbol some believe of ancient worshiping.

"Considering the scale of the burial site and the mysterious cultural signs, the analyses of the relics are going to yield some exciting results," predicted Idelisi.

The State Administration of Cultural Heritage approved excavation of the Xiaohe tombs in 2003.

(China Daily March 19, 2005)

mtDNA from Xinjiang

A new study quantifies the level of Caucasoid admixture in various populations of the Xinjiang province of China, which ranges from 0% in the Han Chinese to 43% in the Uygur.

Mol Biol Evol. 2004 Aug 18 [Epub ahead of print]

Different Matrilineal Contributions to Genetic Structure of Ethnic Groups in the Silk Road Region in China.

Yao YG

Previous studies have shown that there were extensive genetic admixtures in the Silk Road region. In the present study, we analyzed 252 mtDNAs of five ethnic groups (Uygur, Uzbek, Kazak, Mongolian, and Hui) from Xinjiang Province, China (where once was the via route of the Silk Road), together with some reported data from the adjacent regions in Central Asia. In a simple way, we classified the mtDNAs into different haplogroups (monophyletic clades in the rooted mtDNA tree) according to the available phylogenetic information and compared their frequencies to show the differences among the matrilineal genetic structures of these populations with different demographic histories. With the exception of 8 unassigned M(*), N(*) and R(*) mtDNAs, all the mtDNA types identified here belonged to defined subhaplogroups of haplogroups M and N (including R) and consisted of subsets of both the eastern and western Eurasian pools, thus providing direct evidence in supporting the suggestion that Central Asia be the place of the genetic admixture of the East and the West. Although our samples were from the same geographic location, a decreasing tendency of the western Eurasian-specific haplogroup frequency was observed, with the highest frequency present in Uygur (42.6%) and Uzbek (41.4%), followed by Kazak (30.2%), Mongolian (14.3%), and Hui (6.7%). No western Eurasian type was found in Han Chinese samples from the same place. The frequencies of the eastern Eurasian-specific haplogroups also varied in these samples. Combined with the historical records, ethno-origin, migratory history, and marriage custom might play different roles in shaping the matrilineal genetic structure of different ethnic populations resided in this region.

Link (pdf)

mtDNA of ancient central Asians

An interesting new paper confirms the anthropological and archaeological picture of a westward spread of Caucasoids in Central Asia in early prehistoric times, followed by the spread of Mongoloids in the opposite direction during the 1st millennium BC. The Caucasoid-Mongoloid hybrid population resulting from these interactions is similar in terms of mtDNA with present-day Central Asians with some noted differences (e.g., presence of additional West Eurasian haplogroups). In the ancient samples, West Eurasian haplogroups H, HV, I, T*, T1, U*, U1, U5, U5a1 and W were represented:

• HV sequences have matches in the Central Mediterranean region
• H sequences are split between the common Cambridge Reference Sequence (CRS) found in many populations, and two other sequences found in the Central Mediterranean and the Caucasus
• The I sequence is present in a modern Central Asian and also in individuals from the Caucasus
• The W sequence is widespread in West Eurasia
• T* sequences are widespread in Europe, the Near East and the Central Mediterranean region
• T1 is widespread in West Eurasia, but also found sporadically in East Eurasia
• The U1a sequences are found in Turks, Armenians and Caucasians
• The U5a sequence has been found in an Egyptian
• The U5a1 sequence is frequent in the Caucasus and present in Europe, while a different U5a1 was reported previously in Mongolia

The East Eurasian haplogroups belong to A*, M*, M4 and G2:

• The M* sequence was observed in an Indian individual
• The M4 sequence has not been previously reported
• The G2 sequence is found in present-day China and Central Asia
• One A sequence is found in present-day Central Asians and Indians, while the other two have a motif found in a modern Chukchi

Most (78%) of the sequences are of West Eurasian (Caucasoid) origin, but before the 7th c. BC, East Eurasian (Mongoloid) sequences are absent, although they could be present up to 20.6% (p<0.05).

Proc R Soc Lond B Biol Sci. 2004 May 7;271(1542):941-7. 

Unravelling migrations in the steppe: mitochondrial DNA sequences from ancient central Asians.

Lalueza-Fox C et al.

This study helps to clarify the debate on the Western and Eastern genetic influences in Central Asia. Thirty-six skeletal remains from Kazakhstan (Central Asia), excavated from different sites dating between the fifteenth century BC to the fifth century AD, have been analysed for the hypervariable control region (HVR-I) and haplogroup diagnostic single nucleotide polymorphisms (SNPs) of the mitochondrial DNA genome. Standard authentication criteria for ancient DNA studies, including multiple extractions, cloning of PCR products and independent replication, have been followed. The distribution of east and west Eurasian lineages through time in the region is concordant with the available archaeological information: prior to the thirteenth-seventh century BC, all Kazakh samples belong to European lineages; while later an arrival of east Eurasian sequences that coexisted with the previous west Eurasian genetic substratum can be detected. The presence of an ancient genetic substratum of European origin in West Asia may be related to the discovery of ancient mummies with European features in Xinjiang and to the existence of an extinct Indo-European language, Tocharian. This study demonstrates the usefulness of the ancient DNA in unravelling complex patterns of past human migrations so as to help decipher the origin of present-day admixed populations.

Link (pdf)