Dental morphological evidence for European admixture in Mongolia and western China

Lee, C. and Scott, G. R. (2011), Brief communication: Two-rooted lower Canines—A European trait and sensitive indicator of admixture across Eurasia. American Journal of Physical Anthropology, 146: 481–485. doi: 10.1002/ajpa.21585

With the exception of Carabelli's trait, the European dentition is better known for the morphological traits that it does not exhibit rather than the ones that it does. One root trait, however, runs counter to the characterization of reduced and simplified European crowns and roots. Although a rare trait in general, two-rooted lower canines are much more common in Europeans than in any other regional grouping and, given adequate sample sizes, can be useful in evaluating gene flow between Europeans and neighboring groups. In European samples, two-rooted lower canines consistently exhibit frequencies of 5–8%. In our sample from northern Spain, the trait attains a frequency of almost 10%. In contrast, in Sub-Saharan Africans the trait is virtually unknown while in Asian and Asian-derived populations, it varies between 0.0 and 1.0%. Here we show that two-rooted canine frequencies for new migrants along the western frontiers of China and Mongolia ranged from 0–4%. These data suggest European-derived populations migrated into western China (Xinjiang Province) and Mongolia (Bayan Olgii Aimag) sometime during the late Bronze age (1000–400 BCE). [. . .]

One of the major concerns of Alexandersen (1963) regarding two-rooted lower canines revolved around the issue of ‘‘atavism.’’ This term, rarely used today, begs the question of whether or not this double rooted form was common at one time, then disappeared, only to reappear sometime later. Swindler (1995) notes that ‘‘the deciduous and permanent canines in the majority of living primates have a single root.’’ This suggests that two-rooted lower canines are not the ancestral condition in anthropoids or hominoids. Rather, the phenotype is a derived condition, found primarily in recent human populations distributed across Western Eurasia.

The presence of the two-rooted canines in East Asia may provide some clue as to the eastward migration of new populations into China and Mongolia. The largest numbers of individuals with this trait are concentrated along the western and northern frontiers of China and Mongolia. Archaeological excavations support the large scale movement of people into this area during the Bronze age (ca. 2200 BCE–400 BCE). Burial artifacts and settlement patterns suggest cultural and technological ties to the Afanasevo culture in Siberia, which in turn is linked archaeologically, linguistically, and genetically with the Indo-European Tocharian populations that appear to have migrated to the Tarim Basin ca. 4,000 years ago (Ma and Sun, 1992; Ma and Wang, 1992; Mallory and Mair, 2000; Romgard, 2008; Keyser et al., 2009; Li et al., 2010).

The appearance of a new population on the western frontier also supports the findings of previous research in cranial metrics, dental nonmetrics, and DNA. Using cranial metrics and archaeological dating, Han (1994) hypothesized the earliest large-scale migration into western China occurred during the early Bronze age (2000 BCE) from Central Asia or southern Siberia. Dental nonmetric data also support multiple migrations into western China (Xinjiang Province) from Central Asia during the Bronze age to Iron age (Lee, 2007; Zhang, 2010). mtDNA studies on archaeological and modern population samples from Xinjiang Province show heterogeneous Asian and European genetic signatures dating from the Bronze age to the present (Yao et al., 2004; Cui et al., 2010; Zhang et al., 2010; Li et al., 2010).

As the frequency of two-rooted canines is highest in European samples and low to nonexistent in Asians, we propose this trait was introduced into East Asia by Indo- European speaking groups or their affines crossing the western frontier of China and Mongolia. Further data are needed to clarify aspects of these population movements, including the identity of the migrants, along with the number, routes, and timing of the migrations.

Although two-rooted lower canines cannot offer the precision of DNA in evaluating the ancestry in individual skulls, this trait is a sensitive indicator of admixture wherever Europeans come in contact with Asian or African populations. As this distinctive trait can be scored with relative ease in large samples, it provides a useful supplemental tool in discerning gene flow between distantly related populations going back many millennia.

Haplogroup C mtDNA in Caucasoids does not necessarily indicate "Mongoloid" admixture

Dienekes writes:

Jean M links to a Master's thesis, which discovered the following:

While most of our samples possessed mtDNA haplotypes that can be linked to European and Near Eastern populations, three Neolithic and all three Bronze Age individuals belonged to mtDNA haplogroup C, which is common in East Eurasian, particularly South Siberian, populations but exceedingly rare in Europe. Phylogeographic network analysis revealed that our samples are located at or near the ancestral node for haplogroup C and that derived lineages branching from the Neolithic samples were present in Bronze Age Kurgans. In light of the numerous examples of mtDNA admixture that can be found in both Europe and Siberia, it appears that the NPR and South Siberia are located at opposite ends of a genetic continuum established at some point prior to the Neolithic. This migration corridor may have been established during the Last Glacial Maximum due to extensive glaciation in northern Eurasia and a consequent aridization of western Asia. This implies the demographic history for the European gene pool is more complex than previously considered and also has significant implications regarding the origin of Kurgan populations.

[. . .] The Dnieper-Donets population was described as robust Europeoid by Soviet anthropologists as was the Andronovo/Afanasevo tradition further east. It is interesting that Mongoloid admixture has been detected in both groups. I would not have guessed that this would have extended that far west and south. It seems that M. G. Levin may have been right when he stated that the Mongoloid elements penetrated far into eastern Europe.

I see no reason to believe the presence of haplogroup C indicates a "Mongoloid component". Stephen Oppenheimer sees C/Z mtDNA entering Mongoloids as part of an "intrusive" element "likely to have arrived from farther west in Asia, along with the eastern spread of the Upper Palaeolithic technology that appeared in Kara Bom in the Russian Altai 43,000 years ago." If this is correct, the presence of C in robust steppe Caucasoids would not be surprising. Oppenheimer has C/Z originating in western South Asia and entering Central Asia "round the western end of the Himalayas" 40-50,000 years ago, whereas Mongoloids (and "real" East Eurasian haplogroups) ultimately originate in SE Asia. Rather than indicating Mongoloid admixture "penetrated far into Eastern Europe", the presence of C mtDNA this early and this far west means one can't simply write off C and Z lineages in more easterly ancient Caucasoids (like some of those those buried at Xiaohe) -- or in Icelanders, for that matter -- as the product of Mongoloid admixture.

From Oppenheimer's Out of Eden:

Victor Mair talk on Tarim Basin Mummies

Part of a series of lectures related to the "Secrets of the Silk Road" exhibition at the University of Pennsylvania Museum of Archaeology and Anthropology. The mummy and artifacts abruptly pulled from the exhibition by the Chinese government before it opened are back for now.

Two old papers on Tarim Basin mummies / crania

Now available online at the Sino-Platonic Papers website.

Dolkun Kamberi, "The Three Thousand Year Old Charchan Man" Sino-Platonic Papers, 44 (January, 1994)

The male would have been two meters tall when living (see color plates I and IIa); the corpse was lying on its right side with legs bent and propped up by a small piece of wood (perhaps to promote preservation by means of circulation of air around the corpse). The hair, eyelashes, beard and chest hair were intact and traces of makeup (ocher spiral sun-symbols) could be seen on the face. The presence in the tomb of two small bone spoons with dried ocher pigment in them may indicate that the makeup was applied after death. The male's head hair was yellowish brown half gone to white;

Note: More recent estimates put Cherchen Man's height closer to 5'9".

HAN Kangxin: "The Study of Ancient Human Skeletons from Xinjiang, China" Sino-Platonic Papers, 5 1 (November, 1994)

Between 1920 and 1940, only three foreign scientists published completed research in this area. They are: Arthur Keith of England (1929), Carl-Herman Hjortsjo and Ander Walander of Germany (1924) and A.N. Iuzefovich of the USSR (1949). A total of twenty skulls were described. Five came from the northern part of the Taklamakan Desert and Keith thought they characterized the "Loulan racial type." Eleven skulls were collected by Sven Hedin from near Luobubo (Lopnor) in 1928 and 1934, and have been subdivided into three groups (Nordic, Chinese, and Alpine) by Hjortsjo and Walander. The remaining skulls also came from the Luobubo (Lopnor) area and exhibit Mongoloid characteristics. Iuzefovich considered these to be of Tujue (Turkish) origin (Keith, A., 1929; Hjortsjo, C.H. and A. Walander, 1942; Iusefovich, A.N., 1949). [. . .]

Chinese scientists have conducted systematic excavations in this region since 1940. I have studied all the skeletal material housed at the Institute of Archeology of Xinjiang and analyzed the physical and racial characteristics of these human bones. The materials included about 274 skulls which were collected from nine ancient cemeteries in Xinjiang. The cemeteries range in age from about 1800 B.C.E. to 300 C.E.

Ancient DNA from Small River Cemetery Number 5

Someone asked about the reference to Siberian admixture in the NYT article on Ordek's necropolis. According to the paper reporting the DNA results, the majority of individuals tested belonged to a branch of haplogroup C4 that shows some similarities to one found among "Evenks and Udegeys of southeastern Siberia". Other mtDNA lineages detected include H and K. All Y chromosomes tested belonged to haplogroup R1a1a.

The shared sequences of the Xiaohe C haplotype (S1) were distributed in southeastern Siberia. It implies that the east Eurasian component in the Xiaohe people originated from the Siberian populations, especially the southern or eastern Siberian populations.

The mtDNA haplogroup H is the most common mtDNA haplogroup in Europe, especially in northwestern Europe, and its frequency can be as high as 65% in Iberia. Frequencies gradually decrease from the northwest to the southeast of Europe. By contrast, the frequency of haplogroup H rises to only 20% in the Near East, and to less than10% in Central Asia, and is very low in East Asia [33,34]. All of the shared sequences of the Xiaohe H haplotype, however, were distributed in Western Europe. Haplogroup K is also common in Europe, particularly around the Alps and the British Isles. It is found with less frequency in North Africa, the Middle East, and South Asia [21,35-37]. Considering the presence of haplogroups H and K in the Xiaohe people and the geographical distribution of shared sequences, we conclude that the west Eurasian component observed in the Xiaohe people originated from western European, and maternal ancestry of the Xiaohe people might have close relationship with western European.

Regarding the Y chromosomal DNA analyses, the seven males identified all belonged to haplogroup R1a1a. It is most frequently found in Eastern Europe, South Asia and Siberia. In contrast, it is relatively uncommon in Middle Easterners and rare in East Asian [22-24]. It is thought to be a trace of the migration events of early Indo-European [38,39]. The presence of haplogroup R1a1a in the ancient Xiaohe people implies that the parental ancestry of the Xiaohe people originated from somewhere in Siberia or Europe, which is consistent with the origin of maternal ancestry.

[Chunxiang Li et al. Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age. BMC Biology 2010, 8:15doi:10.1186/1741-7007-8-15.]

Small River Cemetery Number 5

A New York Times article from last month on Ördek's Necropolis:

All the men who were analyzed had a Y chromosome that is now mostly found in Eastern Europe, Central Asia and Siberia, but rarely in China. The mitochondrial DNA, which passes down the female line, consisted of a lineage from Siberia and two that are common in Europe. Since both the Y chromosome and the mitochondrial DNA lineages are ancient, Dr. Zhou and his team conclude the European and Siberian populations probably intermarried before entering the Tarim Basin some 4,000 years ago.

The Small River Cemetery was rediscovered in 1934 by the Swedish archaeologist Folke Bergman and then forgotten for 66 years until relocated through GPS navigation by a Chinese expedition. Archaeologists began excavating it from 2003 to 2005. Their reports have been translated and summarized by Victor H. Mair, a professor of Chinese at the University of Pennsylvania and an expert in the prehistory of the Tarim Basin. [. . .]

Several items in the Small River Cemetery burials resemble artifacts or customs familiar in Europe, Dr. Mair noted. Boat burials were common among the Vikings. String skirts and phallic symbols have been found in Bronze Age burials of Northern Europe.

Folke Bergman's 1939 report, Archaeological Researches in Sinkiang, is available online at the Digital Archive of Toyo Bunko Rare Books, along with expedition records from Sven Hedin, Aurel Stein, and others. Ördek was Sven Hedin's Turkish servant, who after being inspired by what he saw working for Hedin discovered the cemetery on a tomb robbing expedition in search of buried treasure. From Bergman:

STEIN emphasizes the non-Mongolian features of the Lop-nor mummies, and I have been able, on the whole, to confirm his statement. One or two of the mummified heads at Cemetery 5 had, however, broad cheek-bones giving them a "Mongolian" look, but this might be due to the individual variations that occur in every race or type

More ancient DNA results from Xinjiang

I'm unfamiliar with the site and I haven't read the paper, but based on the dates mentioned (~500 BC to 1 AD) these results again most likely have little or no bearing on the question or the origins of the older, Northern European-looking mummies (which date to as early as ~1800 BC).

Sci China C Life Sci. 2008 Mar;51(3):205-13.

Mitochondrial DNA analysis of human remains from the Yuansha site in Xinjiang, China.

Gao S, Cui Y, Yang Y, Duan R, Abuduresule I, Mair VH, Zhu H, Zhou H.

Laboratory of Ancient DNA, Research Center for Chinese Frontier Archaeology, Jilin University, Changchun, 130012, China.

The Yuansha site is located in the center of the Taklimakan Desert of Xinjiang, in the southern Silk Road region. MtDNA was extracted from fifteen human remains excavated from the Yuansha site, dating back 2,000-2,500 years. Analysis of the phylogenetic tree and the multidimensional scaling (MDS) reveals that the Yuansha population has relatively close relationships with the modern populations of South Central Asia and Indus Valley, as well as with the ancient population of Chawuhu.

PMID: 18246308 [PubMed - indexed for MEDLINE]

Some ancient DNA results from the Tarim Basin

Note: some clown references this paper on Wikipedia in the following context:

The cemetery at Yanbulaq contained 29 mummies which date from 1800–500 BC, 21 of which are Caucasoid—the earliest Caucasoid mummies found in the Tarim Basin—and eight of which are of the same Caucasoid physical type found at Qäwrighul.[1]:237 . However, more recent genetic studies painted a more complex picture (Xie et al., 2007). It showed both european and asian characteristics.

In fact, this study has no bearing on the origins of the Northern Europoid "Tarim mummies". Sampul is a much later site, which according to physical anthropologists was populated primarily by Central Asian "Eastern Mediterranean" types. Mallory and Mair discuss the findings of Han Kangxin:

The Qäwrighul remains are relatively homogeneous and they exhibit features associated with a type known as Proto-Europoid, a rather robust Caucasoid, especially well represented in Northern Europe and the steppelands and forest-steppe of Russia and the Ukraine. Similar remains occur in the Bronze Age cemeteries of southern Siberia, Kazakhstan, Central Asia and the Lower Volga. [. . .]

The next oldest remains derive from the Yanbulaq cemetery near Humul (Hami), situated to the northeast of Qäwrighul and the easternmost cemetery investigated. Here Han Kangxin identified 21 of the 29 complete skulls as Mongoloids and these are the earliest definite evidence of Mongoloids in East Central Asia. The remaining skulls, however, belonged to Caucasoids who are closest to those from Qäwrighul and point to the same general direction for their origins, i.e. the steppelands to the north and west.

The single skull recovered from among the inhumation burials at Shambalay near Tahkurgan in the far west of the Tarim Basin has been compared with the type that spanned the Mediterranean across Central Asia; this type also includes the Saka tribes of the southern Pamirs.

A much larger sample of 58 skulls was recovered from one of the mass graves at Alwighul in the Tangri Tagh (Tian Shan). Here Han distinguishes two Caucasoids types: the Eastern Mediterranean or Indo-Afghan type with their long and high skulls and the broader and rounder skulls of the Pamir-Ferghana type; Han also identified hybrids of these two subtypes as well as some evidence of Mongoloid admixture. By now, the attentive reader will know we owe another caveat; the three physical types employed by Han Kangxin -- Proto-Europoids, Indo-Afghans and Pamir-Ferghanans -- are largely relabelled Nordics, Mediterraneans, and Alpines, terms that send shivers of apprehension down the spines of Western biological anthropologists.

[. . .]

The Sampul cemetery provides us with our only physical anthropological evidence of the southern Silk Road in the vicinity of Khotan. Although the cemetery contained various individual graves employing some form of log coffin, all the burials examined derive from the group graves which date to the first centuries BC. Han Kangxin has identified the remains as belonging to the same Indo-Afghan type that one encounters among the Saka of the southern Pamirs.

[pp. 236-239; The Tarim Mummies]

Progress in Natural Science, Volume 17, Number 8, pp. 927-933(7)

Mitochondrial DNA analysis of ancient Sampula population in Xinjiang

Xie Chengzhi Li Chunxiang Cui Yinqiu Cai Dawei Wang Haijing Zhu Hong Zhou Hui

Abstract: The archaeological site of 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 analyzed by 364 bp of the mitochondrial DNA hypervariable region I (mtDNA HVR-I), 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.

Keywords: ancient DNA mitochondrial DNA Sampula ancient populations

[link]

The authors detect the following haplogroups: U3 (in four individuals), N (x2), C (x2), B, F1a, G, M, and T2.