Results obtained in five years in a paternity testing laboratory in Mexico

Abstract

Although national and international organizations regularly report information from paternity testing labs in different countries, Latin American countries are scarcely included in these reports. For that reason, the aim of this study was to describe different parameters from 3005 paternity tests analyzed in a Mexican laboratory (www.dnaprofile.com.mx) over a period of five years. Motherless paternity tests were the most frequent (77.27%), followed by cases including the mother (20.70%), whereas the remaining included different reconstruction cases (2.04%). The exclusion rate was 29.58%, into the range reported by the AABB (American Association of Blood Banks). We detected 65 mutations, involving one and two steps (93.8 and 6.2%, respectively). The average mutation rate for the autosomal STR loci was estimated (7.8×10−4). Five triallelic patterns and 12 suspected null alleles were detected; however, null alleles were not confirmed by re-amplification, suggesting that actually most of them are mutations. We evaluated the informativity apportioned by Human Identification (HID) kits used for motherless tests in this lab in two ways: (i) when non-paternity was concluded, by the number of mismatches detected (exclusions); and (ii) when the kinship was deduced, by the estimated paternity index (PI) and paternity probability (W). In brief, it was evident that the large majority of motherless paternity tests can be successfully solved with 20 STRs. This report will be a useful reference for the paternity testing activity in Mexico and Latin America.