Genetic diversity of the chromosome X in aboriginal Siberian populations: The structure of linkage disequilibrium and haplotype phylogeography of the ZFX locus

Abstract

The gene pool structure of aboriginal Siberian populations has been described based on the polymorphism of the ZFX gene located on the chromosome X. In the ten populations studied, 49 haplotypes were present, three of them with high frequencies. Comparison of the obtained results with the available data from the HapMap project revealed unique African haplotypes that occurred in the Yoruba with the frequency of 3–7% and were not found in other populations. The genetic differentiation coefficient of the Siberian ethnic groups studied was 0.0486. Correlation analysis using Mantel’s test did not detect significant correlations between the genetic distance matrix and the matrices of geographic, linguistic, and anthropological differences, although the correlation with the anthropological matrix was the highest. Phylogenetic analysis proved strong isolation of the African population from the other ethnic groups investigated. The Siberian populations were divided into two separate clusters: the first one included Yakuts, Buryats, and Kets, while the second cluster included Altaians, Tuvinians, and Khanty. Using the principal component analysis, the populations were combined into three groups clearly differing by manifestation of Caucasoid and Mongoloid components. The first group included residents of Europe and one of Khanty populations, the second group included populations of South Siberia and residents of China. Mongoloid populations of East Siberia, the Japanese, and Kets were combined into the third group. Barrier analysis revealed a similar structure of genetic differentiation of Siberian populations. Linkage disequilibrium structure was obtained for six ethnic groups of Siberia. In five of them (except for the Ket population), ten ZFX SNPs formed a single linkage block.