Phylogenetic analyses of the 19 STR loci in X chromosome revealed discriminant forensic characteristics for Chinese Daur and Oroqen minorities

In respect of forensic genetics, X-STRs are widely applied for deficiency paternity cases. Given the popularization of AGCU-X19 STR Kit in China, there has been investigation conducted into the genetic data and forensic parameters of 19 X-STR loci in many of the Chinese ethnic groups, which makes it possible to perform nationwide phylogenetic comparation. To evaluate the allele and haplotype diversity of 19 X-STR loci and to explore their forensic efficiency in the Daur and Oroqen minorities, unrelated healthy Daur (n = 86) and Oroqen (n = 165) individuals were recruited from Heilongjiang province, so as to reveal the phylogenetic relationship between the two minorities and other Chinese ethnic groups. Of the Daur and Oroqen minorities, 172 and 183 alleles at the 19 X-STR loci were observed, respectively. Haplotype diversity exceeded 0.9 among all the linkage clusters. High cumulative value was observed for the power of discrimination, the probability of exclusion, and the mean exclusion chance for deficiency cases (normal trios and duo cases). As revealed by this study, the panel of 19 X-STR loci is an effective supplementary tool for the kinship test of the studied nationalities.