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.
Cooper EA, Whittall JB, Hodges SA, Nordborg M (2010) Genetic Variation at Nuclear Loci Fails to Distinguish Two Morphologically Distinct Species of Aquilegia. PLoS ONE 5(1): e8655. doi:10.1371/journal.pone.0008655
This work was supported by an NSF grant: EF-0412727. The funders had no role in study design, data collection and analysis, decision to publish, orpreparation of the manuscript.