Mutation analysis of 21autosomal short tandem repeats in Han population from Hunan, China

Background: Short tandem repeats (STRs), are powerful genetic markers widely used in human genetics. Population data and locus-specific mutation rates of STRs are crucial for the evaluation and interpretation of genetic evidence in forensic and population genetics. Aim: To investigate the mutation rates of 21 autosomal STRs in a population from central south China. Subjects and methods: We analysed 3,420 paternity cases with a Combined Paternity Index≧10,000 from Han population in Hunan. A total of 68,743 meiotic transfers were analysed and 62 mutations were identified. Results: The overall mutation rate of STR loci was 0.9 x10⁻³ (95%CI, 0.0007-0.0011) , and the locus-specific mutation rates were estimated ranging from 0.0000 to 0.0023. Locus D1S1656 exhibited the highest mutation rate of 2.3 x10⁻³ (95%CI, 0.0005-0.0006) , followed by D12S391 with a mutation rate of 2.0 x10⁻³ (95%CI, 0.0007-0.0044) . No mutation was observed at TPOX, D2S1338 or Penta D. One-step mutation cases accounted for 96.77% of total mutations and the ratio of paternal versus maternal mutations was about 4.85:1. Conclusion: Inter-population comparisons of locus-specific mutation rates of several STRs revealed significant difference between Han in Hunan and Han in other regions in China. Our data support the use of geographical data in further genetic applications.