Mutation analysis of 24 autosomal STR loci using in paternity testing

Abstract

To obtain the knowledge about the locus-specific mutation rate and characteristics of 24 autosomal STR loci, fifteen STR loci ( D31358 et al.) were typed with the PowerPlex ® 16 system (Promega, USA) for 11175 DNA-confirmed paternity testing cases (8059 trios, 1978 father-child duos and 1138 mother-child duos), and nine STR loci (D2S1772 et al.) were typed with the STRtyper ®-10F/G system (Condon, China) for 4046 DNA-confirmed paternity testing cases (2115 trios and 1227 father-child duos and 704 mother-child duos). A total of 343,959 meiotic transfers were analyzed and 488 mutations were identified. The overall average mutation rate was estimated as 0.00142 and the estimated locus-specific mutation rate varied between 0.00010 and 0.00422. Mostly only one mutation occurred in a case, while there were 20 cases with double mutations and 2 cases with triple mutations investigated with 24 STR loci genotyping. One-step mutation was accounted for 98.16% of total mutations. The ratio of paternal versus maternal mutation was 3.66:1. Except for those two cases with triple mutations, the combined paternity index (CPI) value of 24 STR loci was greater than 10,000 when calculated including the mutation loci.