human neutral genetic variation and forensic str data人类中性基因变异和法医str数据.pdfVIP

Human Neutral Genetic Variation and Forensic STR Data 1 ´ 1,2 3 3 Nuno M. Silva , Luısa Pereira , Estella S. Poloni , Mathias Currat * 1 IPATIMUP (Instituto de Patologia e Imunologia Molecular da Universidade do Porto), Universidade do Porto, Porto, Portugal, 2 Faculdade de Medicina, Universidade do Porto, Porto, Portugal, 3 Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution - Anthropology Unit, University of Geneva, Geneva, Switzerland Abstract The forensic genetics field is generating extensive population data on polymorphism of short tandem repeats (STR) markers in globally distributed samples. In this study we explored and quantified the informative power of these datasets to address issues related to human evolution and diversity, by using two online resources: an allele frequency dataset representing 141 populations summing up to almost 26 thousand individuals; a genotype dataset consisting of 42 populations and more than 11 thousand individuals. We show that the genetic relationships between populations based on forensic STRs are best explained by geography, as observed when analysing other worldwide datasets generated specifically to study human diversity. However, the global level of genetic differentiation between populations (as measured by a fixation index) is about half the value estimated with those other datasets, which contain a much higher number of markers but much less individuals. We suggest that the main factor explaining this difference is an ascertainment bias in forensics data resulting from the choice of markers for individual identification. We show that this choice results in average low variance of heterozygosity across world regions, and hence in