Forensic statistical parameters of 22 autosomal STRs in Mestizos from the Peninsula of Yucatán, México

Abstract

The Mestizo (admixed) population of the Peninsula of Yucatan (Southeast, México) characterizes by a predominant Native American origin involving the Mayan culture. Autosomal Short tandem repeats (STRs) are the election tool for human identification (HID) purposes, such as forensic casework and paternity testing, among others. Although there are autosomal STR databases for some Mexican populations, the HID kits with more STRs have poorly studied in this country. Therefore, we estimated forensic parameters for 22 autosomal STRs belonging to the PowerPlex® Fusion System Promega kit (Promega, Corp.) in a population sample of 733 Mexican Mestizos subjects from the Peninsula of Yucatán (Southeast, Mexico). Buccal swabs were used as DNA sample for direct PCR multiplex amplification for genotyping PowerPlex® Fusion System Promega kit. Forensic parameters were obtained with Powerstats 1.2 software. Hardy-Weinberg expectations (HWE) were estimated with GDA ver 1.1 software. Gene diversity was estimated with Shannon-Wiener (H`) and statistical differences with t-test modified by Hutcheson using Biodiv 5.1 software. Interpopulation comparisons were analyzed with Dice and Rogers-Tanimoto indexes and classification method of Unweighted Pair-Group Method (UPGMA). Genotype distribution was in agreement with HWE (p > 0.001), except for D1S1656. FGA and Penta E were the most polymorphic loci with 32 and 25 different alleles, respectively. Heterozygosity ranged from 0.6112 for D22S1045 to 0.9141 for D1S1656. The most discriminating loci were Penta E (0.9852) and FGA (0.9756). The combined power of discrimination and combined power of exclusion were 1.9093 × 10−26 and 99.9999833%, respectively. Gene diversity ranged from 1.21 for D22S1045 to 2.68 for Penta E. Inter-comparison populations did not show significant differences for gene diversity based on allelic frequencies of 22 studied autosomal STR. Our results provide a STR population dataset that allow confident interpretation of paternity tests and criminal cases carried out with this HID system in the Peninsula of Yucatan.