Diagnostic SNPs reveal widespread introgressive hybridization between introduced bighead and silver carp in the Mississippi River Basin

摘要: Hybridization among conspecifics in native and introduced habitats has important implications for biological invasions new ecosystems. Bighead (Hypophthalmichthys nobilis) silver carp (H. molitrix) are genetically isolated occur sympatry within their range. Following introduction to North America, however, introgressant hybrids have been reported throughout expanded range the Mississippi River Basin (MRB). The extent of introgression, both spatially generationally, is largely unknown. Therefore, we examined mixed-species populations from across MRB characterize interspecific gene flow. We assayed 2798 individuals nine locations with a suite species-diagnostic SNPs (57 nuclear one mitochondrial). Forty-four per cent (n = 1244) displayed hybrid genotypes. Moreover, composition genotypes varied represented complex swarms multiple generations Introgressive were identified all locations, bidirectional followed bimodal distribution consisting primarily parental or parental-like phenotypes. All described categories present 1999 2008, parents later-generation backcrosses representing largest proportion years. Our mitochondrial SNP (COII), tested on subset 730 individuals, revealed maternal bias 13 21 (62%) F1 hybrids, backcrosses, maintained many bighead backcrosses. application this diagnostic markers spatial coverage permits deeper examination complexity between two invasive, species.