Genetic polymorphisms for 19 X-STR loci of Sichuan Han ethnicity and its comparison with Chinese populations

X-chromosomal short tandem repeats (X-STRs) can be serviced as a complementary tool in forensic deficiency cases and other complicated kinship identification. To investigate the genetic variation of the western Chinese Han population, genetic polymorphisms of 19 X-STR loci (DXS8378, DXS7423, DXS10148, DXS10159, DXS10134, DXS7424, DXS10164, DXS10162, DXS7132, DXS10079, DXS6789, DXS101, DXS10103, DXS10101, HPRTB, DXS6809, DXS10075, DXS10074 and DXS10135) included in the AGCU X19 PCR amplification kit were obtained from 201 Chinese Han individuals (108 females and 93 males) residing in Sichuan province, western China. A total of 211 alleles were found from the 19 X-STR loci, and 4-22 alleles were found for each locus with the corresponding allele frequencies spanned from 0.0034 to 0.6395. The combined PDF and PDM were 0.9999999999999999999992 and 0.9999999999997, respectively. The combined MECKruger, MECKishida, MECDesmarais, as well as MECDesmarais Duo were 0.999999958110254, 0.999999999996533, 0.999999999996695 and 0.999999992428394, respectively. The number of haplotypes observed in the seven linkage groups varied from 27 to 97 for 108 male individuals with the corresponding haplotype diversities spanned from 0.9424 (DXS7424-DXS101) to 0.9979 (DXS7132-DXS10079-DXS10075-DXS10074). The above-mentioned results indicated that the 19 X-STR loci and the seven linkage groups are highly polymorphic and informative in the Sichuan Han population. Results from population comparisons and phylogenetic analyses demonstrated that genetic heterogeneity widely existed between the Sichuan Han population and Xinjiang minority ethnic groups (Uyghur and Kazakh) and genetic affinity was identified in populations which possessed the same ethno-origin or close geographic origin.