title: Introgressive Hybridization and the Evolution of Lake-Adapted Catostomid Fishes.
abstract: Hybridization has been identified as a significant factor in the evolution of plants as groups of interbreeding species retain their phenotypic integrity despite gene exchange among forms. Recent studies have identified similar interactions in animals; however, the role of hybridization in the evolution of animals has been contested. Here we examine patterns of gene flow among four species of catostomid fishes from the Klamath and Rogue rivers using molecular and morphological traits. Catostomus rimiculus from the Rogue and Klamath basins represent a monophyletic group for nuclear and morphological traits; however, the Klamath form shares mtDNA lineages with other Klamath Basin species (C. snyderi, Chasmistes brevirostris, Deltistes luxatus). Within other Klamath Basin taxa, D. luxatus was largely fixed for alternate nuclear alleles relative to C. rimiculus, while Ch. brevirostris and C. snyderi exhibited a mixture of these alleles. Deltistes luxatus was the only Klamath Basin species that exhibited consistent covariation of nuclear and mitochondrial traits and was the primary source of mismatched mtDNA in Ch. brevirostris and C. snyderi, suggesting asymmetrical introgression into the latter species. In Upper Klamath Lake, D. luxatus spawning was more likely to overlap spatially and temporally with C. snyderi and Ch. brevirostris than either of those two with each other. The latter two species could not be distinguished with any molecular markers but were morphologically diagnosable in Upper Klamath Lake, where they were largely spatially and temporally segregated during spawning. We examine parallel evolution and syngameon hypotheses and conclude that observed patterns are most easily explained by introgressive hybridization among Klamath Basin catostomids.
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Dowling
authors.affiliation: Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Markle
authors.affiliation: Department of Animal Science, University of California Davis, Davis, California, United States of America.
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Tranah
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America.
authors.forename: Evan W
authors.initials: EW
authors.lastname: Carson
authors.affiliation: Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: David W
authors.initials: DW
authors.lastname: Wagman
authors.affiliation: Department of Animal Science, University of California Davis, Davis, California, United States of America.
authors.forename: Bernard P
authors.initials: BP
authors.lastname: May
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics; D003531:Cypriniformes / Q000033:anatomy & histology / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D005819:Genetic Markers; D005828:Genetics, Population; D006239:Haplotypes / Q000235:genetics; D006579:Heterozygote; D006720:Homozygote; D006824:Hybridization, Genetic; D060106:Lakes; D010802:Phylogeny
chemical_list: D004272:DNA, Mitochondrial; D005819:Genetic Markers