Genetic Polymorphisms and Mutations of 30 Y-STR Loci in Chinese Han Population

OBJECTIVES:To investigate the genetic polymorphisms and mutations of 30 Y-STR loci in Chinese Han males and to evaluate its forensic application.METHODS:The DNA extracted from blood samples of 1 005 unrelated males and 1 008 father-son pairs （1 949 individuals in all） in Chinese Han population were typed using developed 30 Y-STR loci identification system. The parameters of population genetics and the mutation rates of each locus were analysed statistically.RESULTS:A total of 983 haplotypes were found in 1 005 unrelated males from Chinese Han population, of which 963 were unique. The overall haplotype diversity （HD） and discrimination capacity （DC） were 0.999 955 and 0.978 109, respectively. Totally 340 alleles were detected on 30 Y-STR loci, the value of gene diversity （GD） ranged from 0.410 3 to 0.952 3. The GD values of 24 out of the 30 loci were over 0.6. There were 30 269 allele transfers in 1 008 father-son pairs, one mutation in 68 father-son pairs, and the mutation of three father-son pairs occurred at two loci. On 26 Y-STR loci, 74 mutations were detected in 71 father-son pairs. The average mutation rates were 2.4×10⁻³ （95% CI： 1.9×10⁻³-3.1×10⁻³）. Seventy-three mutation events were one-step mutation （98.6%）, 1 mutation event was two-step mutation （1.4%）.CONCLUSIONS:The multiplex PCR system with 30 Y-STR loci has high genetic polymorphism and low mutation rates in Chinese Han males. Therefore, the system shows important values in Y-STR database construction and population genetic research.