The Genetic Echo of the Tarim Mummies in Modern Central Asians.

The diversity of Central Asians has been shaped by multiple migrations and cultural diffusion. Although ancient DNA studies have revealed the demographic changes of the Central Asian since the Bronze Age, the contribution of the ancient populations to the modern Central Asian remains opaque. Herein, we performed high-coverage sequencing of 131 whole genomes of Indo-European-speaking Tajik and Turkic-speaking Kyrgyz populations to explore their genomic diversity and admixture history. By integrating the ancient DNA data, we revealed more details of the origins and admixture history of Central Asians. We found that the major ancestry of present-day Tajik populations can be traced back to the admixture of the Bronze Age Bactria-Margiana Archaeological Complex and Andronovo-related populations. Highland Tajik populations further received additional gene flow from the Tarim mummies, an isolated ancient North Eurasian-related population. The West Eurasian ancestry of Kyrgyz is mainly derived from Historical Era populations in Xinjiang of China. Furthermore, the recent admixture signals detected in both Tajik and Kyrgyz are ascribed to the expansions of Eastern Steppe nomadic pastoralists during the Historical Era.

Tracing the Genetic Legacy of the Tibetan Empire in the Balti.

The rise and expansion of Tibetan Empire in the 7th to 9th centuries AD affected the course of history across East Eurasia, but the genetic impact of Tibetans on surrounding populations remains undefined. We sequenced 60 genomes for four populations from Pakistan and Tajikistan to explore their demographic history. We showed that the genomes of Balti people from Baltistan comprised 22.6-26% Tibetan ancestry. We inferred a single admixture event and dated it to about 39-21 generations ago, a period that postdated the conquest of Baltistan by the ancient Tibetan Empire. The analyses of mitochondrial DNA, Y, and X chromosome data indicated that both ancient Tibetan males and females were involved in the male-biased dispersal. Given the fact that the Balti people adopted Tibetan language and culture in history, our study suggested the impact of Tibetan Empire on Baltistan involved dominant cultural and minor demic diffusion.

The evolutionary genetics of lactase persistence in seven ethnic groups across the Iranian plateau.

BACKGROUND: The ability to digest dietary lactose is associated with lactase persistence (LP) in the intestinal lumen in human. The genetic basis of LP has been investigated in many populations in the world. Iran has a long history of pastoralism and the daily consumption of dairy products; thus, we aim to assess how LP has evolved in the Iranian population. We recruited 400 adult individuals from seven Iranian ethnic groups, from whom we investigated their lactose tolerance and screened the genetic variants in their lactase gene locus. RESULTS: The LP frequency distribution ranged from 0 to 29.9% in the seven Iranian ethnic groups with an average value of 9.8%. The variants, - 13910*T and - 22018*A, were significantly associated with LP phenotype in Iranians. We found no evidence of hard selective sweep for - 13910*T and - 22018*A in Persians, the largest ethnic group of Iran. The extremely low frequency of - 13915*G in the Iranian population challenged the view that LP distribution in Iran resulted from the demic diffusion, especially mediated by the spread of Islam, from the Arabian Peninsula. CONCLUSIONS: Our results indicate the distribution of LP in seven ethnic groups across the Iranian plateau. Soft selective sweep rather than hard selective sweep played a substantial role in the evolution of LP in Iranian populations.

Correction to: The evolutionary genetics of lactase persistence in seven ethnic groups across the Iranian plateau.

AbstractIn the original publication of this article [1], the colors of the Fig. 1 are wrong, and are revised in the updated figure below.

Author Correction: 863 genomes reveal the origin and domestication of chicken.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

863 genomes reveal the origin and domestication of chicken.

Despite the substantial role that chickens have played in human societies across the world, both the geographic and temporal origins of their domestication remain controversial. To address this issue, we analyzed 863 genomes from a worldwide sampling of chickens and representatives of all four species of wild jungle fowl and each of the five subspecies of red jungle fowl (RJF). Our study suggests that domestic chickens were initially derived from the RJF subspecies Gallus gallus spadiceus whose present-day distribution is predominantly in southwestern China, northern Thailand and Myanmar. Following their domestication, chickens were translocated across Southeast and South Asia where they interbred locally with both RJF subspecies and other jungle fowl species. In addition, our results show that the White Leghorn chicken breed possesses a mosaic of divergent ancestries inherited from other subspecies of RJF. Despite the strong episodic gene flow from geographically divergent lineages of jungle fowls, our analyses show that domestic chickens undergo genetic adaptations that underlie their unique behavioral, morphological and reproductive traits. Our study provides novel insights into the evolutionary history of domestic chickens and a valuable resource to facilitate ongoing genetic and functional investigations of the world's most numerous domestic animal.

Mitochondrial genomes uncover the maternal history of the Pamir populations.

The Pamirs, among the world's highest mountains in Central Asia, are one of homelands with the most extreme high altitude for several ethnic groups. The settlement history of modern humans on the Pamirs remains still opaque. Herein, we have sequenced the mitochondrial DNA (mtDNA) genomes of 382 individuals belonging to eight populations from the Pamirs and the surrounding lowlands in Central Asia. We construct the Central Asian (including both highlanders and lowlanders) mtDNA haplogroup tree at the highest resolution. All the matrilineal components are assigned into the defined mtDNA haplogroups in East and West Eurasians. No basal lineages that directly emanate from the Eurasian founder macrohaplogroups M, N, and R are found. Our data support the origin of Central Asian being the result of East-West Eurasian admixture. The coalescence ages for more than 93% mtDNA lineages in Central Asians are dated after the last glacial maximum (LGM). The post-LGM and/or later dispersals/admixtures play dominant roles in shaping the maternal gene pool of Central Asians. More importantly, our analyses reveal the mtDNA heterogeneity in the Pamir highlanders, not only between the Turkic Kyrgyz and the Indo-European Tajik groups, but also among three highland Tajiks. No evidence supports positive selection or relaxation of selective constraints in the mtDNAs of highlanders as compared to that of lowlanders. Our results suggest a complex history for the peopling of Pamirs by multiple waves of migrations from various genetic resources during different time scales.

[Association of waist-to-hip ratio with insulin resistance in non-diabetic normal-weight individuals: a cross-sectional study].

OBJECTIVE: To explore the relationship between waist-to-hip ratio (WHR) and insulin resistance(IR) in non-diabetic normal-weight individuals and investigate how this association differs between male and femalesubjects. METHODS: From June to October, 2012, we performed a cross-sectional survey among 2142 community-based non-diabetic Chinese participants, who were divided into 4 groups according to the gender-specific quartiles of WHR. Homeostatic model assessment of insulin resistance (HOMA-IR), calculated as the product of fasting plasma glucose (mmol/L) and fasting insulin (mU/L) divided by 22.5, was used as the indicator of insulin resistance. Logistic regression models were used to explore the association of WHR with IR in these subjects. RESULTS: In the unadjusted model, WHR was significantly associated with IR in women (OR=6.60, 95%CI: 2.86-15.26, P<0.001); the association was still significant (OR=3.28, 95%CI: 1.34-8.04, P=0.009) after adjustment for the potential confounders including the history of hypertension, coronary heartdisease, current smoker, physical inactivity, and body mass index. CONCLUSION: WHR is independently associated with IR in non-diabetic Chinese women with normal body weight.