Mutation rates in 21 autosomal short tandem repeat loci in a population from Goiás, Brazil

The appearance of new mutations in polymorphic markers plays a central role in a range of genetic applications, including dating phylogenetic events, informing disease studies, and evaluating forensic evidence. The present study estimated the mutation rates of 21 autosomal STR loci in a population from Central Brazil. We studied 15 046 paternity cases from Goiás, Brazil from August 2012 to February 2015. We identified 262 mutations in the 21 loci. The loci that presented more mutations were FGA and D18S51, with a total of 46 and 28 mutations, respectively. The results showed mutational rates ranging from 1.7 × 10−5 to 7.6 × 10−4 mutations per site/region and the overall mutational rate was 2.1 × 10−4; these values were within the expected values for the STR markers. The most common type of mutation was one‐step mutation, which totaled 96.2%. We found a higher rate of mutations of paternal origin (67.6%) than of mutations of maternal origin. The occurrence of mutations in STRs has important consequences for human identification, including the definition of criteria for exclusion in paternity testing and interpretation of genetic profiles in criminal cases.