Abstract:【Objective】 To investigate the genetic polymorphisms and mutations of 27 Y-STR loci in Chinese Southern Han population. 【Methods】 Blood samples of 885 unrelated male individuals and 911 father-son pairs were collected. DNA was amplified and genotyped using YfilerRPlus system. The forensic parameters and mutation rates were calculated. 【Results】 880 different haplotypes were observed in 885 unrelated male individuals

of which 875 haplotypes were unique

5 haplotypes occurred twice. The haplotype diversity (HD) was 0.9999872 with discriminative capacity (DC) 0.9943503. The gene diversity at the 27 Y-STR loci ranged from 0.4344 (DYS438) to 0.9605 (DYS385a/b). With 24623 allele transfers at 911 father-son pairs

113 mutation events were detected

of which 108 mutations were single-repeat mutations

five mutations were two-step mutations. 11 father-son pairs had mutations at two different loci

while 1 father-son pair was found to have three mutations. The average mutation rate was 4.6 × 10-3 (95% CI: 3.8 × 10-3 ~ 5.5 × 10-3). 【Conclusion】 27 Y-STR loci incorporated in YfilerR Plus system are highly polymorphic in Chinese Southern Han population. They are of great importance in forensic individual discrimination and paternal lineage testing.