Inference of population structure using multilocus genotype data

We describe a model-based clustering method for using multilocus genotype d ata to infer population structure and assign individuals to populations. We assume a model in which there are K populations (where K may be unknown), each of which is characterized by a set of allele frequencies at each locus . Individuals in the sample are assigned (probabilistically) to populations , or jointly to two or more populations if their genotypes indicate that th ey are admixed. Our model does not assume a particular mutation process, an d it can be applied to most of the commonly used genetic markers, provided that they are not closely linked. Applications of our method include demons trating the presence of population structure, assigning individuals to popu lations, studying hybrid zones, and identifying migrants and admired indivi duals. We show that the method can produce highly accurate assignments usin g modest numbers of loci-e.g., seven microsatellite loci in an example usin g genotype data from an endangered bird species. The software used for this article is available from http://www.stats.ox.ac.uk/similar to pritch/home .html.