Identificação e caracterização de mutações slippage em marcadores microssatélites autossômicos de interesse forense em uma população do sudeste brasileiro

Abstract

Well-defined estimates of mutation rates in highly polymorphic tetra-nucleotide short tandem repeats (STR) loci are a prerequisite for human identification (paternity) in the routines of civil and criminal investigations. Studding 15 autosomal STR loci of forensic interest (CSF1PO, D13S317, D16S539, D18S51, D19S433, D21S11, D2S1338, D3S1358, D5S818, D7S820, D8S1179, FGA, TH01, TPOX and vWA) we detected 193 slippage mutations (189 one-step and 4 two-step mutations) in 148,875 parent–child allelic transfers from 5,171 paternity cases with true biological relationship (15,096 individuals; 4,754 trios and 417 duos; 9,925 meioses). The overall mutation rate was 1.3x10-3. The highest rates were observed in vWA (2.8x10-3), FGA and D18S51 (2.7x10-3 for both) loci, while TH01 and TPOX loci presented no mutations in this populational sample. Mean slippage mutation rate of paternal origin (1.8x10-3) was six times higher than that observed from maternal origin (0.3x10-3), except for locus D21S11.