title: Rangewide molecular structuring in the Utah sucker (Catostomus ardens).
abstract: The Utah sucker (Catostomus ardens) is endemic to the Bonneville Basin and the upper Snake River drainage in western North America, and is thought to hybridize with the federally endangered June sucker (Chasmistes liorus mictus) in Utah Lake (Bonneville Basin). Here we describe the discovery of a major subdivision in Utah suckers (4.5% mitochondrial sequence divergence) between the ancient Snake River drainage and the Bonneville Basin. This boundary has not previously been recognized in Utah suckers based on morphologic variation, but has been recently described in two endemic cyprinids in the region. Populations in valleys east of the Wasatch Mountains in Utah clustered with the Snake River populations, suggesting that these valleys may have had an ancient hydrologic connection to the Snake River. We also found evidence of population isolation within the Bonneville Basin, corresponding to two Pleistocene sub-basins of the ancient Lake Bonneville. In contrast, we found no molecular evidence for deep divergence between Utah suckers and June suckers in Utah Lake or for a history of hybridization between divergent lineages in that population, although we recognize that demographic events may have obscured this signal. These findings suggest that the morphological differences between Utah and June suckers in Utah Lake may be the result of strong, and relatively recent, ecological selection. In summary, morphological and molecular characters seem to vary along different axes in different portions of the range of this taxon, providing an interesting system for studying the contributions of neutral and adaptive variation to species diversity.
authors.affiliation: Department of Forest, Range, and Wildlife Sciences, Utah State University, Logan, Utah 84322-5230, USA. karen.mock@usu.edu
authors.forename: K E
authors.initials: KE
authors.lastname: Mock
authors.forename: R P
authors.initials: RP
authors.lastname: Evans
authors.forename: M
authors.initials: M
authors.lastname: Crawford
authors.forename: B L
authors.initials: BL
authors.lastname: Cardall
authors.forename: S U
authors.initials: SU
authors.lastname: Janecke
authors.forename: M P
authors.initials: MP
authors.lastname: Miller
mesh_terms: D000818:Animals; D003531:Cypriniformes / Q000235:genetics*; D004272:DNA, Mitochondrial; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D006824:Hybridization, Genetic; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D017422:Sequence Analysis, DNA; D014589:Utah
chemical_list: D004272:DNA, Mitochondrial; D005819:Genetic Markers