title: Distinguishing between incomplete lineage sorting and genomic introgressions: complete fixation of allospecific mitochondrial DNA in a sexually reproducing fish (Cobitis; Teleostei), despite clonal reproduction of hybrids.
abstract: Distinguishing between hybrid introgression and incomplete lineage sorting causing incongruence among gene trees in that they exhibit topological differences requires application of statistical approaches that are based on biologically relevant models. Such study is especially challenging in hybrid systems, where usual vectors mediating interspecific gene transfers--hybrids with Mendelian heredity--are absent or unknown. Here we study a complex of hybridizing species, which are known to produce clonal hybrids, to discover how one of the species, Cobitis tanaitica, has achieved a pattern of mito-nuclear mosaic genome over the whole geographic range. We appplied three distinct methods, including the method using solely the information on gene tree topologies, and found that the contrasting mito-nuclear signal might not have resulted from the retention of ancestral polymorphism. Instead, we found two signs of hybridization events related to C. tanaitica; one concerning nuclear gene flow and the other suggested mitochondrial capture. Interestingly, clonal inheritance (gynogenesis) of contemporary hybrids prevents genomic introgressions and non-clonal hybrids are either absent or too rare to be detected among European Cobitis. Our analyses therefore suggest that introgressive hybridizations are rather old episodes, mediated by previously existing hybrids whose inheritance was not entirely clonal. Cobitis complex thus supports the view that the type of resulting hybrids depends on a level of genomic divergence between sexual species.
authors: Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, v.v.i., Libechov, Czech Republic; Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland.
authors: Lukas
authors: L
authors: Choleva
authors: Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, v.v.i., Libechov, Czech Republic; Zoological Institute, Evolutionary Biology, University of Basel, Basel, Switzerland; Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic.
authors: Zuzana
authors: Z
authors: Musilova
authors: Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, v.v.i., Libechov, Czech Republic; Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia.
authors: Alena
authors: A
authors: Kohoutova-Sediva
authors: Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, v.v.i., Libechov, Czech Republic; Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the ASCR, v.v.i., Prague, Czech Republic.
authors: Jan
authors: J
authors: Paces
authors: Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, v.v.i., Libechov, Czech Republic.
authors: Petr
authors: P
authors: Rab
authors: Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, AS CR, v.v.i., Libechov, Czech Republic; Life Science Research Centre, Department of Biology and Ecology, Faculty of Natural Sciences, University of Ostrava, Ostrava, Czech Republic.
authors: Karel
authors: K
authors: Janko
mesh_terms: D000818:Animals; D003531:Cypriniformes / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D019143:Evolution, Molecular; D049810:Genetic Speciation; D016678:Genome; D006824:Hybridization, Genetic; D012098:Reproduction
chemical_list: D004272:DNA, Mitochondrial