Display Settings:

Format

Send to:

Choose Destination
We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Plant Cell. 2006 Aug;18(8):1803-18. Epub 2006 Jun 23.

A genome-wide survey of R gene polymorphisms in Arabidopsis.

Author information

  • 1Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA.

Abstract

We used polymorphism analysis to study the evolutionary dynamics of 27 disease resistance (R) genes by resequencing the leucine-rich repeat (LRR) region in 96 Arabidopsis thaliana accessions. We compared single nucleotide polymorphisms (SNPs) in these R genes to an empirical distribution of SNP in the same sample based on 876 fragments selected to sample the entire genome. LRR regions are highly polymorphic for protein variants but not for synonymous changes, suggesting that they generate many alleles maintained for short time periods. Recombination is also relatively common and important for generating protein variants. Although none of the genes is nearly as polymorphic as RPP13, a locus previously shown to have strong signatures of balancing selection, seven genes show weaker indications of balancing selection. Five R genes are relatively invariant, indicating young alleles, but all contain segregating protein variants. Polymorphism analysis in neighboring fragments yielded inconclusive evidence for recent selective sweeps at these loci. In addition, few alleles are candidates for rapid increases in frequency expected under directional selection. Haplotype sharing analysis revealed significant underrepresentation of R gene alleles with extended haplotypes compared with 1102 random genomic fragments. Lack of convincing evidence for directional selection or selective sweeps argues against an arms race driving R gene evolution. Instead, the data support transient or frequency-dependent selection maintaining protein variants at a locus for variable time periods.

PMID:
16798885
[PubMed - indexed for MEDLINE]
PMCID:
PMC1533970
Free PMC Article

Images from this publication.See all images (6)Free text

Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.

Publication Types, MeSH Terms, Substances, Secondary Source ID, Grant Support

Publication Types

MeSH Terms

Substances

Secondary Source ID

Grant Support

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk