Balancing selection and low recombination affect diversity near the self-incompatibility loci of the plant Arabidopsis lyrata

Curr Biol. 2005 Oct 11;15(19):1773-8. doi: 10.1016/j.cub.2005.08.062.

Abstract

The self-incompatibility (S-) locus region of plants in the Brassica family is a small genome region. In Arabidopsis lyrata, the S-genes, SRK and SCR, encode the functional female and pollen recognition proteins, which must be coadapted to maintain correct associations between the two component genes, and thus self-incompatibility (SI). Recombinants would be self-compatible and thus probably disadvantageous in self-incompatible species. Therefore, tight linkage between the two genes in incompatibility systems is predicted to evolve to avoid producing such recombinant haplotypes. The evolution of low recombination in S-locus regions has not been rigorously tested. To test whether these regions' per-nucleotide recombination rates differ from those elsewhere in the genome, and to investigate whether the A. lyrata S-loci have the predicted effect on diversity in their immediate genome region, we studied diversity in genes that are linked to the S-loci but are not involved in incompatibility and are not under balancing selection. Compared with other A. lyrata loci, genes linked to the S-loci have extraordinarily high polymorphism. Our estimated recombination in this region, from fitting a model of the effects of S-allele polymorphism on linked neutral sites, supports the hypothesis of locally suppressed recombination around the S-locus.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis Proteins / genetics
  • Base Sequence
  • DNA Primers
  • Genes, Plant / genetics*
  • Genetic Linkage*
  • Molecular Sequence Data
  • Plant Proteins / genetics
  • Polymorphism, Genetic*
  • Protein Kinases / genetics
  • Recombination, Genetic / genetics*
  • Selection, Genetic*
  • Sequence Analysis, DNA

Substances

  • Arabidopsis Proteins
  • DNA Primers
  • Plant Proteins
  • SCR protein, Arabidopsis
  • Protein Kinases
  • S-receptor kinase

Associated data

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