Meeting Abstract

118.2  Tuesday, Jan. 7 10:30  The genetic architecture of reproductive isolation between naturally hybridizing species SCHUMER, M; CUI, R*; POWELL, D; ROSENTHAL, G; ANDOLFATTO, P; Princeton University; Texas A&M University; Texas A&M University; Texas A&M University; Princeton University melop@tamu.edu

Maintenance of species boundaries upon secondary contact is crucial to the speciation process. The Bateson-Dobzhansky-Muller model posits that epistatic effects between genomic loci inherited from different ancestries may prevent gene-flow by reducing hybrid fitness. Wild hybrid zones serve as good models for looking into BDM incompatibility. However, population genetic histories, such as bottlenecks and genetic drift, could confound the effect of selection and produce false positive linkage disequilibrium between unlinked loci. We identify genome-wide patterns of BDM incompatibility in two independent Xiphophorus birchmanni x X. malinche natural hybrid zones using a novel application of the Multiplexed Shotgun Genotyping (MSG) technique. Simulations show that using consensus LD information from two heterogeneous hybrid populations effectively reduces false-positive associations. We found numerous (~150), narrow unlinked genomic regions in LD. The majority of these LD pairs are enriched for conspecific ancestry, supporting the BDM model.