The most frequent autosomal STRs involved in exclusion of paternity cases in a population from southeast, Mexico

Introduction: Short tandem repeats (STR) are very widespread in the human genome; being a source of polymorphic markers, used for the determination of kindship. Few studies indicate the frequency of autosomal STR involved in the exclusion of paternity, as well as, those with a higher percentage of discordance. determine the distribution and frequency of the main autosomal STR markers involved in the exclusion of paternity cases in an admixed population from Southeast, Mexico (Peninsula de Yucatan). Methods: 91 cases of excluded paternity, were included in the study: 61 trios and 30 motherless. All subjects belong to an admixed population with Mayan ethnicity from Southeast of Mexico. PowerPlex Fusion System (PPFS) was used for genotyping. The distribution and frequency of the autosomal STRs involved in each case of paternity exclusion were recorded based on 22 autosomal STR of PPFS. Results: The number of STR which determined the exclusion in all cases ranged from 5 to 18 markers, being up to 14 STR for motherless cases. Paternity exclusions occurred most frequently with 13-STRs (22.22%) for trios and 9-STRs (37.5%) for motherless cases. The autosomal STR with the highest percentage of discordance is PENTA-E, for all cases 69.23%, 85.25% for trios. For motherless cases were D1S1656 and PENTA-E (36.67%,both). Conclusions: The most frequent number of autosomal STR marker to confer a paternity exclusion was 13, the most informative STR marker for exclusions was PENTA-E.