title: Genetic variation at nuclear loci fails to distinguish two morphologically distinct species of Aquilegia.
abstract: Aquilegia formosa and pubescens are two closely related species belonging to the columbine genus. Despite their morphological and ecological differences, previous studies have revealed a large degree of intercompatibility, as well as little sequence divergence between these two taxa. We compared the inter- and intraspecific patterns of variation for 9 nuclear loci, and found that the two species were practically indistinguishable at the level of DNA sequence polymorphism, indicating either very recent speciation or continued gene flow. As a comparison, we also analyzed variation at two loci across 30 other Aquilegia taxa; this revealed slightly more differentiation among taxa, which seemed best explained by geographic distance. By contrast, we found no evidence for isolation by distance on a more local geographic scale. We conclude that the extremely low levels of genetic differentiation between A. formosa and A. pubescens at neutral loci will facilitate future genome-wide scans for speciation genes.
authors.affiliation: Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America. eacooper@usc.edu
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Cooper
authors.forename: Justen B
authors.initials: JB
authors.lastname: Whittall
authors.forename: Scott A
authors.initials: SA
authors.lastname: Hodges
authors.forename: Magnus
authors.initials: M
authors.lastname: Nordborg
mesh_terms: D031884:Aquilegia / Q000145:classification* / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics*; D014644:Genetic Variation; D015810:Linkage Disequilibrium; D011110:Polymorphism, Genetic; D013045:Species Specificity