Journal de recherche médico-légale

Action Protocols in DNA Identification of Isolated Populations

Abstract

Maria Saiz MS, Maria J Alvarez-Cubero, Juan C Alvarez, Luis J Martinez-Gonzalez and Jose A Lorente

This paper presents the basic problems and difficulties that can be found when working with isolated populations as far as propose some approaches in the analysis of this type of populations. 13 autosomal STRs have been analyzed and statistical forensic parameters, such as observed heterozygosity and power of discrimination have been determined, in samples from isolated and non-isolated populations. Samples were amplified with AmpFlSTR®Identifiler® kit (Applied Biosystems) and PowerPlex 16®kit (Promega). For DNA typing, an ABI PRISM 310 Genetic Analyzer was used, and the analysis was performed with GeneMapper ID-X Software v1.1. PowerStats software and SPSS v15.0 were used to calculate forensic and other parameters.The analysis is based on the comparison of three main population groups (large, medium, and small), and an estimation of the forensic parameters, such as discrimination power (PD), observed heterozygosity (Ho), and combined PD, was obtained.The obtained results reveal that heterozygosity and PD are lower in aboriginal populations than in other populations. This research contributes to defining the decrease in allele presence caused by the lower size of a population as far as endogamy processes.To obtain an efficient human identification, it is necessary to generate independent databases for all the different populations, including small isolated groups. Action protocols to these kinds of populations have to be adapted: type as many markers as possible, not only autosomal STR but also mitochondrial DNA and sexual chromosome markers and characterize those one that better describe the population, and also get genetic information of close relatives as far as direct references of the individual.