Mutation rate evaluation at 21 autosomal STR loci: Paternity testing experience

The short tandem repeats (STRs) or microsatellites are used for paternity testing and these sequences mutate more rapidly than bulk DNA sequences. A total of 746 paternity cases were analysed to understand the mutation rate of 21 autosomal STR loci. We identified 41 mutations in 11 STR Loci with a maximum at SE33. No mutations occurred in the remaining 10 STR loci. The overall average mutation rate was estimated as 0.004523 and the estimated locus-specific mutation rate varied between 0.001214 and 0.016990. Among these 90.24% was accounted for single-step mutation, 2.44% for two steps, and 7.32 % for three or muti steps. The obtained data is crucial and could be helpful for ensuring the accuracy of DNA testing and interpretation.