Comparative genomic and population genetic analyses indicate highly porous genomes and high levels of gene flow between divergent helianthus species

Nolan C. Kane, Matthew G. King, Michael S. Barker, Andrew Raduski, Sophie Karrenberg, Yoko Yatabe, Steven J. Knapp, Loren H. Rieseberg

Research output: Contribution to journalArticle

92 Scopus citations

Abstract

While speciation can be found in the presence of gene flow, it is not clear what impact this gene flow has on genome- and range-wide patterns of differentiation. Here we examine gene flow across the entire range of the common sunflower, H. annuus, its historically allopatric sister species H. argophyllus and a more distantly related, sympatric relative H. petiolaris. Analysis of genotypes at 26 microsatellite loci in 1015 individuals from across the range of the three species showed substantial introgression between geographically proximal populations of H. annuus and H. petiolaris, limited introgression between H. annuus and H. argophyllus, and essentially no gene flow between the allopatric pair, H. argophyllus and H. petiolaris. Analysis of sequence divergence levels among the three species in 1420 orthologs identified from EST databases identified a subset of loci showing extremely low divergence between H. annuus and H. petiolaris and extremely high divergence between the sister species H. annuus and H. argophyllus, consistent with introgression between H. annuus and H. petiolaris at these loci. Thus, at many loci, the allopatric sister species are more genetically divergent than the more distantly related sympatric species, which have exchanged genes across much of the genome while remaining morphologically and ecologically distinct.

Original languageEnglish (US)
Pages (from-to)2061-2075
Number of pages15
JournalEvolution
Volume63
Issue number8
DOIs
StatePublished - Aug 2009

Keywords

  • EST
  • Hybridization
  • Introgression
  • Microsatellites
  • Speciation
  • Sunflower

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Agricultural and Biological Sciences(all)

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