Genetic structure and forensic characterisation of 19 X-chromosomal STR loci in Guizhou Sui population

Abstract

Background: Guizhou Sui people are an officially recognised ethnic group living in southwest China, but have seldom been studied genetically. Aim: To investigate the polymorphisms of 19 X-chromosome STR loci in a typical Sui population and enrich the East Asian X-STR reference database for forensic DNA analysis. Subjects and methods: We genotyped a total of 400 individuals (195 males and 205 females) of Sui at 19 X-STR loci using the AGCU X19 STR Kit. We calculated and illustrated the allele frequencies, forensic parameters, and merged our data of Guizhou Sui with 18 other nationwide populations to explore genetic polymorphisms and population relationships. Results: We observed a total of 215 alleles with corresponding frequencies ranging from 0.0017 to 0.6512 in Sui using male and female pooled allele frequencies. We observed large values, at least 0.9999999933, in combined powers of discrimination of Sui males and females, as well as the four mean paternity exclusion chances (MECs). The phylogenetic analysis among 19 populations showed that Sui have close genetic affinities with other Tai-Kadai populations as well as the Sinitic populations living in southern China. Conclusions: The AGCU X-19 STRs are highly polymorphic and informative in Guizhou Sui people. The genetic relationships between Sui and other populations in China are generally consistent with the language classification and geographical distance.