Abstract
The Khoton Mongolian population is a small and relatively isolated ethnic group residing predominantly in the northwestern part of
Mongolia. A recent genetic study of the Y chromosome revealed that the major Mongolian ethnic groups have a relatively close genetic
affinity to populations in the northern part of East Asia, while the Khoton population reflected an apparent genetic differentiation from the
other Mongolian populations. To further investigate the genetic features of the Khoton and the other Mongolian populations, we analyzed the
single nucleotide polymorphisms (SNPs) in the Xq13.3 region, which is thought to have an extremely low level of recombination in the
human X chromosome. We found that the frequency distribution of Xq13.3 haplotypes in the Khoton population was substantially different
from those in three other Mongolian populations (Khalkh, Uriankhai, and Zakhchin). The same relationship was also revealed by the results
from the population tree and principal-component (PC) analysis based on the allele frequencies. These results are largely consistent with the
hypothesis that the Khoton population descended from a nomadic tribe of Turkish origin, which has been supported by previous
anthropological, historical, and Y-chromosome studies. However, the population structure analysis produced an additional finding, namely,
that the Khoton population is likely to be an admixed population.
D 2005 Elsevier B.V. All rights reserved.
Keywords: Mongolian; X chromosome; TaqMan assay; SNP haplotype; Population structure