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

Abstract

BackgroundThe 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.ResultsXiaohe 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.ConclusionOur 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0237-5) contains supplementary material, which is available to authorized users.

Origin and spread of human mitochondrial DNA haplogroup U7

“…This haplogroup is characterized by generally low population frequencies and limited sequence diversity, despite a geographic distribution ranging from Europe to India1416252730313233. Recently, it has been detected in skeletal remains from Southwest Iran dated ~six thousand years ago (kya)34 as well as in remains from the Tarim Basin in Northwest China (3.5–4.0 kya)35.…”

Phylogenetic and population structural inference from genomic ancestry maintained in present‐day common wheat Chinese landraces

“…Considering the morphological changes resulting from ancient preservation, molecular methods have been widely adopted to ascertain the genomic identity of archeological plant samples of interest in population studies (Li et al ., ; Bilgic et al ., ; Fornaciari et al ., ; Mascher et al ., ; Wales et al ., ; Di et al ., ). Our Xiaohe ancient wheat seeds were previously determined to be hexaploid based on their longer amplified D‐subgenomic rDNA IGS (intergenic spacer region), which should be absent from the respective regions in the A and B subgenomes (Li et al ., ).…”

“…Xinjiang, as a major geographic intersection between the West and the East, may have played an important role in the eastward spreading of wheat (Millward, ; Li et al ., ). Abundant, well preserved cereal remains, including ancient wheat seeds, have been excavated in several prehistoric cemeteries, such as Xiaohe and Gumugou cemeteries, located in the Taklimakan Desert, and they were determined to have similar radiocarbon dates and archeological context (Xie et al ., ; Li et al ., ). These ancient wheat seeds are a valuable resource for completing individual DNA sequencing to reveal the population evolutionary history of wheat since its entry into China especially for its further spreading within China.…”

New genetic evidence of affinities and discontinuities between bronze age Siberian populations

“…The only Y‐haplogroup found by Li et al () 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. The interpretation of mtDNA results is less categorical, with one haplotype (16,223 16,298 16,327), carried by Afanasievo individuals Kh19 and Kh20, also found in one individual from the Gavaerk site (southern Xinjiang), dated between 2800 BP and 2100 BP (Zhang et al, ), and one individual in the Xiaohe necropolis (on the eastern edge of the Tarim Basin), dated between 4000 BP and 3500 BP (Li et al, ). This mitochondrial haplotype is however considered to be an ancestral haplotype and is commonly found in southern Siberia (Li et al, ).…”

“…The interpretation of mtDNA results is less categorical, with one haplotype (16,223 16,298 16,327), carried by Afanasievo individuals Kh19 and Kh20, also found in one individual from the Gavaerk site (southern Xinjiang), dated between 2800 BP and 2100 BP (Zhang et al, ), and one individual in the Xiaohe necropolis (on the eastern edge of the Tarim Basin), dated between 4000 BP and 3500 BP (Li et al, ). This mitochondrial haplotype is however considered to be an ancestral haplotype and is commonly found in southern Siberia (Li et al, ). Its presence in our samples can therefore not attest to an Afanasievo migration into the Tarim Basin.…”