title: 2BAD: an application to estimate the parental contributions during two independent admixture events.
abstract: Several approaches have been developed to calculate the relative contributions of parental populations in single admixture event scenarios, including Bayesian methods. In many breeds and populations, it may be more realistic to consider multiple admixture events. However, no approach has been developed to date to estimate admixture in such cases. This report describes a program application, 2BAD (for 2-event Bayesian ADmixture), which allows the consideration of up to two independent admixture events involving two or three parental populations and a single admixed population, depending on the number of populations sampled. For each of these models, it is possible to estimate several parameters (admixture, effective sizes, etc.) using an approximate Bayesian computation approach. In addition, the program allows comparing pairs of admixture models, determining which is the most likely given data. The application was tested through simulations and was found to provide good estimates for the contribution of the populations at the two admixture events. We were also able to determine whether an admixture model was more likely than a simple split model.
authors.affiliation: Cardiff School of Biosciences, Cardiff University, P.O. Box 915, Cardiff CF10 3TL, UK Instituto Gulbenkian de Ciência, Rua da Quinta Grande, N°6, P-2780-156 Oeiras, Portugal Faculdade de Ciências da Universidade de Lisboa, Centro de Biologia Ambiental, Campo Grande, Bloco C2-3°Piso, 1749-016 Lisboa, Portugal UMR 5174 CNRS/UPS Evolution et Diversité Biologique, Université Paul Sabatier, 118 Route de Narbonne, Bât. 4R3 b2, 31062 Toulouse cédex 09, France.
authors.forename: T C
authors.initials: TC
authors.lastname: Bray
authors.forename: V C
authors.initials: VC
authors.lastname: Sousa
authors.forename: B
authors.initials: B
authors.lastname: Parreira
authors.forename: M W
authors.initials: MW
authors.lastname: Bruford
authors.forename: L
authors.initials: L
authors.lastname: Chikhi