Maternal allele mutation: Slippage synthesis furnishing evolutionary trend

Abstract

Gain or loss of repeat motifs leads to an allelic mismatch in the disputed child which is a deviation from the Mendelian inheritance, thereby leading to a paternal mismatch of putative father or exclusion of mother in case of maternal allelic mismatch. This allelic mismatch at one or more loci is a major cause of forensic inferences. The biological samples of the case were genotyped using Powerplex®- Fusion 5C system kit and Investigator® Argus X-12 QS kit as per recommendations of the manufacturer. In this case, identification of a putrefied dead body with 22 autosomal STR loci, primarily analyzed by Powerplex®- Fusion 5C system kit divulged a maternal mismatch at locus D13S317. Alleles at the locus D13S317 allegedly belonging to the father of the deceased and the mother were observed as 10/11, 11/11 and 10/10 respectively. To rule out allelic mismatch at this particular locus, 12 X-STR loci were amplified, in which all the maternal alleles of deceased completely matched with the mother. This case study indicates the extension of one microsatellite repeat motif (TATC) at locus D13S317 in the population of Rajasthan. The reported mutation rate was 0.14% and 0.04% at locus D13S317 in paternal and maternal meiosis respectively.