Widespread horizontal genomic exchange does not erode species barriers among sympatric ducks

摘要: Background: The study of speciation and maintenance species barriers is at the core evolutionary biology. During genome one population becomes separated from other populations same species, which may lead to genomic incompatibility with time. This separation complete when no fertile offspring produced inter-population matings, basis biological concept. Birds, in particular ducks, are recognised as a challenging illustrative group higher vertebrates for studies. There many sympatric ecologically similar duck among hybrids occur relatively frequently nature, yet these remain distinct. Results: We show that degree shared single nucleotide polymorphisms (SNPs) between five dabbling ducks (genus Anas) an order magnitude than previously reported any pair eukaryotic comparable distances. demonstrate hybridisation has led sustained exchange genetic material on time scale without disintegrating boundaries. Even though behavioural, ecological factors uphold boundaries we detect opposing forces allowing viable interspecific hybrids, long-term implications. Based superspecies concept here introduce novel term “supra-population” explain persistence SNPs identical by descent within studied despite their history distinct dating back millions years. Conclusions: By reviewing evidence theory, palaeogeography palaeontology propose fundamentally new model accommodate our findings ducks. model, argue, also shed light longstanding unresolved general patterns organisms, e.g. bird groups unusually high rates. Observed parallels horizontal gene transfer bacteria facilitate understanding why have been such evolutionarily successful animals. large potential ability genes resulting dramatic increase effective size counter selective constraints.