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Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea
American Journal of Botany
  • Lex E. Flagel, Iowa State University
  • Ryan Adam Rapp, Iowa State University
  • Corrinne E. Grover, Iowa State University
  • Mark P. Widrlechner, United States Department of Agriculture
  • Jennifer S. Hawkins, University of Georgia
  • Jessie L. Grafenberg, Iowa State University
  • Inés Álvarez, Real Jardín Botánico de Madrid
  • Gyu Young Chung, Andong National University
  • Jonathan F. Wendel, Iowa State University
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The study of recently formed species is important because it can help us to better understand organismal divergence and the speciation process. However, these species often present difficult challenges in the field of molecular phylogenetics because the processes that drive molecular divergence can lag behind phenotypic divergence. In the current study we show that species of the recently diverged North American endemic genus of purple coneflower,Echinacea, have low levels of molecular divergence. Data from three nuclear loci and two plastid loci provide neither resolved topologies nor congruent hypotheses about species-level relationships. This lack of phylogenetic resolution is likely due to the combined effects of incomplete lineage sorting, hybridization, and backcrossing following secondary contact. The poor resolution provided by molecular markers contrasts previous studies that found well-resolved and taxonomically supported relationships from metabolic and morphological data. These results suggest that phenotypic canalization, resulting in identifiable morphological species, has occurred rapidly within Echinacea. Conversely, molecular signals have been distorted by gene flow and incomplete lineage sorting. Here we explore the impact of natural history on the genetic organization and phylogenetic relationships of Echinacea.

This article is from American Journal of Botany 95, no. 6 (June 2008): 756–765, doi:10.3732/ajb.0800049.

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
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Lex E. Flagel, Ryan Adam Rapp, Corrinne E. Grover, Mark P. Widrlechner, et al.. "Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea" American Journal of Botany Vol. 95 Iss. 6 (2008) p. 756 - 765
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