Slippage mutation rates in 15 autosomal short tandem repeat loci for forensic purposes in a Southeastern Brazilian population

Abstract

Slippage mutation rates in 15 autosomal short tandem repeat loci for forensic purposes in a Southeastern Brazilian populationWell-defined estimates of mutation rates in highly polymorphic tetranucleotide STR loci are a prerequisite for human identification in genetics laboratory routines useful for civil and criminal investigations. Studying 15 autosomal STR loci of forensic interest (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPOX, and vWA), we detected 193 slippage mutations (189 one-step and four two-step mutations) in 148 875 parent-child allelic transfers from 5171 paternity cases with true biological relationship (15 096 individuals; 4754 trios and 417 duos; 9925 meiosis) from the state of São Paulo, a very representative population of Brazil. The overall mutation rate was 1.3 × 10 −3 and the highest rates were observed at loci vWA (2.8 × 10 −3 ), FGA and D18S51 (2.7 × 10 −3 for both), while loci TH01 and TPOX did not present any mutations. The mean slippage mutation rate of paternal origin (1.8 × 10 −3 ) was six times higher than that observed for maternal origin (0.3 × 10 −3 ).

DNA Paternıty Testıng wıth Two Mısmatches: Our Experıence

“…Since the father from the Case 1 was 65 years old at the birth of child, we assume that his age could be the cause of mutations occured in both autosomal and X-linked STRs. Considering all aforementioned, knowledge about mutation rates and possible mutational processes of different STR loci is important for accurate genetic profiles interpretation (Qian et al, 2015;Hamester et al, 2019). As previously mentioned in the Introduction section, a number of population-genetic studies, focused on evaluating of forensic efficiency parameters of STR markers (Grskovic et al, 2013 2016; Crnjac et al, 2017;Veselinovic et al, 2018;Al-Eitan et al, 2019;Al-Eitan et al, 2020;Pilav et al, 2020;Takic Miladinov et al, 2020) indicated a high degree of reliability of these markers important for all kinds of forensic-genetic analyses, including kinship and parentage testing.…”

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“…Since the father from the Case 1 was 65 years old at the birth of child, we assume that his age could be the cause of mutations occured in both autosomal and X-linked STRs. Considering all aforementioned, knowledge about mutation rates and possible mutational processes of different STR loci is important for accurate genetic profiles interpretation (Qian et al, 2015;Hamester et al, 2019). As previously mentioned in the Introduction section, a number of population-genetic studies, focused on evaluating of forensic efficiency parameters of STR markers (Grskovic et al, 2013 2016; Crnjac et al, 2017;Veselinovic et al, 2018;Al-Eitan et al, 2019;Al-Eitan et al, 2020;Pilav et al, 2020;Takic Miladinov et al, 2020) indicated a high degree of reliability of these markers important for all kinds of forensic-genetic analyses, including kinship and parentage testing.…”