Genomic islands of divergence are not affected by geography of speciation in sunflowers

S. Renaut, C. J. Grassa, S. Yeaman, B. T. Moyers, Z. Lai, N. C. Kane, J. E. Bowers, J. M. Burke, L. H. Rieseberg

Research output: Contribution to journalArticle

162 Scopus citations

Abstract

Genomic studies of speciation often report the presence of highly differentiated genomic regions interspersed within a milieu of weakly diverged loci. The formation of these speciation islands is generally attributed to reduced inter-population gene flow near loci under divergent selection, but few studies have critically evaluated this hypothesis. Here, we report on transcriptome scans among four recently diverged pairs of sunflower (Helianthus) species that vary in the geographical context of speciation. We find that genetic divergence is lower in sympatric and parapatric comparisons, consistent with a role for gene flow in eroding neutral differences. However, genomic islands of divergence are numerous and small in all comparisons, and contrary to expectations, island number and size are not significantly affected by levels of interspecific gene flow. Rather, island formation is strongly associated with reduced recombination rates. Overall, our results indicate that the functional architecture of genomes plays a larger role in shaping genomic divergence than does the geography of speciation.

Original languageEnglish (US)
Article number1827
JournalNature communications
Volume4
DOIs
StatePublished - Jun 10 2013
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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