Estimating mutation rates in 15 microsatellite autossomal loci in Goiania population, GO

Abstract

The present study had the aim to estimate the mutation rate at 15 STR autossomal loci in Goiania population, GO state, attempting to generate a genetic database of interested for statistical calculations, such as in paternity tests or in studies about induced mutations. Germline mutation of 15 STR loci was studied for 6,450 parent-child transfers from 215 paternity testing cases, all of them carried out in Goiania, from January to December of 2008. We collected blood samples, DNA was extracted and amplified by PCR and the analysis was carried out in the automatic sequencer MEGABACE 500, to obtain the allelic peaks for each genetic marker. We identified 11 mutations in 5 loci. The results indicated that mutation rates varied from 2 to 9 x 10-3 mutations/loci/marker and the total mutation rate was 5 x 10-3. It was found a higher mutation rate of maternal origin, differing of similar studies, probably due to the small number of meiosis analyzed, when compared to the results of another studies. When we analyzed the individual genetic profiles and compared by direct analysis, related to the mutation rates, for each locus, this study presented more gain of repetitive units (54.5%) than losses (45.4%). All the gains involved only one repetitive unit, following the stepwise mutation model. Despite the small sample size, the mutation rates of the 15 autossomal loci showed the importance to incorporate such values in future analysis of paternity tests carried out in Goiania population and nearby attempting to decrease mistakes in paternity tests.