XVI International Botanical Congess

Level and pattern of DNA variation in the nuclear genome of A. thaliana were studied by sequencing, microsatellite and AFLP analyses. Despite selfing nature of this plant species, a high level of DNA variation was found. The estimated nucleotide diversity based on sequence and AFLP variations was about 0.01, and the gene diversity at microsatellite loci was estimated to be 0.79. These values were comparable to those of outcrossing plant and animal species. In three of five genes sequenced, dimorphic variation and intragenic recombinations were detected. Linkage disequilibrium was tested for these variations. The proportion of significant nonrandom associations was close to random expectation. These results suggested that recombination could not be ignored as a mechanism influencing the pattern of DNA variation in the evolutionary history of A. thaliana.