Genetic structure and polymorphisms of Gelao ethnicity residing in southwest china revealed by X-chromosomal genetic markers

X-chromosome short tandem repeat markers (X-STRs), due to their special inheritance models, physical location on a single chromosome and the absence of recombination in male meiosis, play an important role in forensic and population genetics. While a series of genetic analyses focusing on the genetic diversity and forensic characteristics of X-STRs are well studied for ethnically/linguistically diverse and demographically large Chinese populations, genetic evidence from Gelao ethnicity is still sparse. Here, we genotyped the first batch of 19 X-STRs in 513 Chinese Gelao individuals (265 females and 248 males), and reported genetic polymorphisms, forensic characteristics based on the single locus and seven linkage groups. DXS10135 with the highest PIC (0.9106) and LG1 (DXS10148-DXS10135-DXS8378) with the largest HD (0.9970) are polymorphic and informative. The CPDs in Gelao males and females are respectively larger than 0.999999999997095 and 0.99999999999999999999918, and the combined MECs are larger than 0.999999975715109. Subsequently, we investigated the population relationships among 14 Chinese populations based on 19 X-STRs and among 23 populations based on 11 overlapped X-STRs. Our results revealed genetic differentiations among Tibeto-Burman, Altaic and other Chinese homogenous populations, and demonstrated that Guizhou Gelao has the genetically closer relationships with Han Chinese and geographically close Guizhou Miao.