The contribution of genetic diversity to subdivide populations living in the silk road of China.

Zhe Zhang,Shuguang Wei,Shengbin Li,Zuyi Yuan,Hongsheng Gui,Dennis O'Rourke

doi:10.1371/journal.pone.0097344

Abstract

There are several indigenous ethnic populations along the silk road in the Northwest of China that display clear differences in culture and social customs, perhaps as a result of geographic isolation and different linguistic traditions. However, extensive trade and other interactions probably facilitated the admixture of different gene pools between these populations over the last two millennia. To further explore the evolutionary relationships of the 13 ethnic populations residing in Northwest China and to reveal the features of population admixture, the 9 most-commonly employed CODIS loci (D3S1358, TH01, D5S818, D13S317, D7S820, CSF1PO, vWA, TPOX, FGA) were selected for genotyping and further analysis. Phylogenetic tree and principal component analysis revealed clear pattern of population differentiation between 4 populations living in Sinkiang Uighur Autonomous Region and other 9 populations dwelled in the upper regions of Silk Road. R matrix regression showed high-level gene flow and population admixture dose exist among these ethic populations in the Northwest region of China. Furthermore, the Mantel test suggests that larger percent of genetic variance (21.58% versus 2.3%) can be explained by geographic isolation than linguistic barriers, which matched with the contribution of geographic factors to other world populations.

Highlights

The Northwest region of China has a very complex geography, encompassing mountains, plateaus and basins, as well as some special landscapes, such as the Gobi desert
Of the populations that live in Sinkiang Uighur Autonomous Region, all are aboriginals except for the Han ethnic group, which has migrated to the region from Central China since the 1950s
No specific Islamic Lamaismb Islamic Islamic Islamic Islamic Islamic Lamaism Islamic Islamic Islamic No specific a: Han_XA represents the Han population living in Xi’an, while Han_XJ represents the Han population in Sinkiang Uighur Autonomous Region. b: ‘‘Lamaism’’ is a branch of Buddhism that is popular in some regions of China, especially in West China

Summary

Introduction

The Northwest region of China has a very complex geography, encompassing mountains, plateaus and basins, as well as some special landscapes, such as the Gobi desert. Historical records indicate that factors such as religious belief, marriage customs, linguistic traditions and migratory history may have played important roles in shaping the matrilineal genetic structure of the populations living in this region [7] These investigations have seldom examined the genetic structure and population differentiation of the populations living near the starting point of the Silk Road. Genetic markers on the Y chromosome and on mitochondrial DNA, such as Y-STRs, Y-SNPs and mitochondrial hyper-variable regions I and II, have low recombination rates and lack of recombination respectively, are widely used to address the genetic differentiation between populations[13,14]. We have selected 13 representative populations (12 different ethnic groups) living in the Northwest region of China, analyzed the statistical distribution of allele frequency at 9 STR loci, and attempted to reconstruct the genetic structure and reveal the respective gene flows. With these factors in mind, we have quantitatively analyzed the variance components contributed by genetic differentiation, geographic isolation and linguistic differences

Materials and Methods

Results

Discussion