Recombination and gene conversion in a 170-kb genomic region of Arabidopsis thaliana.
Arabidopsis thaliana is a highly selfing plant that nevertheless appears to undergo substantial recombination. To reconcile its selfing habit with the observations of recombination, we have sampled the genetic diversity of A. thaliana at 14 loci of approximately 500 bp each, spread across 170 kb of genomic sequence centered on a QTL for resistance to herbivory. A total of 170 of the 6321 nucleotides surveyed were polymorphic, with 169 being biallelic. The mean silent genetic diversity (pi(s)) varied between 0.001 and 0.03. Pairwise linkage disequilibria between the polymorphisms were negatively correlated with distance, although this effect vanished when only pairs of polymorphisms with four haplotypes were included in the analysis. The absence of a consistent negative correlation between distance and linkage disequilibrium indicated that gene conversion might have played an important role in distributing genetic diversity throughout the region. We tested this by coalescent simulations and estimate that up to 90% of recombination is due to gene conversion.
Max-Planck-Institut für Chemische Okologie, Department of Genetics and Evolution, D-07745 Jena, Germany. bernhard.haubold@lionbioscience.com
Bernhard
B
Haubold
Jürgen
J
Kroymann
Andreas
A
Ratzka
Thomas
T
Mitchell-Olds
Thomas
T
Wiehe
D017360:Arabidopsis / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D005785:Gene Conversion; D018745:Genome, Plant; D015810:Linkage Disequilibrium; D008962:Models, Theoretical; D008969:Molecular Sequence Data; D040641:Quantitative Trait Loci; D011995:Recombination, Genetic
D017931:DNA Primers