genetic variation at nuclear loci fails to distinguish two morphologically distinct species of aquilegia遗传变异在核位点无法区分两种形态不同的物种的耧斗菜.pdfVIP

Genetic Variation at Nuclear Loci Fails to Distinguish Two Morphologically Distinct Species of Aquilegia 1 2 3 4 Elizabeth A. Cooper *, Justen B. Whittall , Scott A. Hodges , Magnus Nordborg 1 Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America, 2 Biology Department, Santa Clara University, Santa Clara, California, United States of America, 3 Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, California, United States of America, 4 Gregor Mendel Institute of Molecular Plant Biology, Vienna, Austria 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 [1,2]. 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. Citation: Cooper EA, Whittall JB, Hodges SA, Nordborg