title: Effects of asymmetric nuclear introgression, introgressive mitochondrial sweep, and purifying selection on phylogenetic reconstruction and divergence estimates in the Pacific clade of Locustella warblers.
abstract: When isolated but reproductively compatible populations expand geographically and meet, simulations predict asymmetric introgression of neutral loci from a local to invading taxon. Genetic introgression may affect phylogenetic reconstruction by obscuring topology and divergence estimates. We combined phylogenetic analysis of sequences from one mtDNA and 12 nuDNA loci with analysis of gene flow among 5 species of Pacific Locustella warblers to test for presence of genetic introgression and its effects on tree topology and divergence estimates. Our data showed that nuDNA introgression was substantial and asymmetrical among all members of superspecies groups whereas mtDNA showed no introgression except a single species pair where the invader's mtDNA was swept by mtDNA of the local species. This introgressive sweep of mtDNA had the opposite direction of the nuDNA introgression and resulted in the paraphyly of the local species' mtDNA haplotypes with respect to those of the invader. Тhe multilocus nuDNA species tree resolved all inter- and intraspecific relationships despite substantial introgression. However, the node ages on the species tree may be underestimated as suggested by the differences in node age estimates based on non-introgressing mtDNA and introgressing nuDNA. In turn, the introgressive sweep and strong purifying selection appear to elongate internal branches in the mtDNA gene tree.
authors: Department of Natural History, Tromsø University Museum, University of Tromsø-The Arctic University of Norway, Tromsø, Norway.
authors: Sergei V
authors: SV
authors: Drovetski
authors: Thematic Group on Bird Ecology, Institute of Systematics and Ecology of Animals of Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia.
authors: Georgy
authors: G
authors: Semenov
authors: Department of Ornithology, Zoological Museum of Moscow State University, Moscow, Russia.
authors: Yaroslav A
authors: YA
authors: Red'kin
authors: Kirov City Zoological Museum, Vyatka, Russia.
authors: Vladimir N
authors: VN
authors: Sotnikov
authors: Department of Collections, State Darwin Museum, Moscow, Russia.
authors: Igor V
authors: IV
authors: Fadeev
authors: Department of Ornithology, Zoological Museum of Moscow State University, Moscow, Russia.
authors: Evgeniy A
authors: EA
authors: Koblik
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D051456:Gene Flow; D056426:Genetic Loci / Q000235:genetics; D008928:Mitochondria / Q000235:genetics*; D010802:Phylogeny; D012641:Selection, Genetic; D020308:Songbirds / Q000145:classification / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial