Rapidly mutating Y-STRs study in Chinese Yi population

Y-chromosomal short tandem repeats (Y-STRs) have been widely used in forensic analysis and population genetics. With low to moderate mutation rates, conventional Y-STR panels, including commercially available Y-STR kits, enable the identification of male pedigrees but typically fail to differentiate related male individuals. The introduction of rapidly mutating Y-chromosomal short tandem repeats (RM Y-STRs) with higher mutation rates (>10(-2)) has been demonstrated to increase the discrimination capacity of unrelated men and the differentiation rate of related men compared with standard Y-STRs. To date, several studies have been performed worldwide. Here, 260 father-son pairs from Chinese Yi population were investigated, and 18.8% of them were differentiated with the 13 RM Y-STR markers, which was close to the theoretical estimate of 19.5% based on the mutation rates of these markers. Among the 57 mutations observed, repeat gains were more common than repeat losses (1.48:1), and one-step mutations were more common than two-step mutations (27.5:1). Locus-specific mutation rates ranged from <3.85x10(-3) (95% CI 0.00-1.41x10(-2)) to 3.85x10(-2) (95% CI 1.86x10(-2)-6.96x10(-2)), with an average mutation rate of 1.46x10(-2) (95% CI 1.11x10(-2)-1.89x10(-2)). Furthermore, we combined the father-son pair data from the present study with the data from the previous studies, generating an overall mutation rate of 1.70x10(-2). The high differentiation rate obtained in the present study indicates the suitability of RM Y-STRs to distinguish paternal lineages in Chinese Yi population.