Genome-Wide Association Mapping in Identifies Previously Known Flowering Time and Pathogen Resistance Genes

There is currentiy tremendous interest im the possibility of using genome-wide association mapping to identify genes responsible for natwal variation, particularly for human disease susceptifoifity. The model plant Awbidopsis thalianü Is in many ways an ideal candidate for such studies, because it is a highly selfing hermaphrodite. Äs a resyft, the species fargely exists as a coifectksn of naturally occurring inbred lines, or accessions, which can be gersotyped once and phenotyped repeatedly. Furthermore, linkage disequilibrium in sych a species wSH be much more extensive than In a comparabie owtcrossing species. We tested the feasibility of genome-wide association mapping in A. thalsana by searching for associations with flowering time and pathogen resistance in a sampae of 95 accessions for which genomewide polymorphism data were available. Sn spite of an extremely high rate of false positives dye to population structure, we were afoie to identify known major genes for all phenotypes testedj thus demonstrating the potential of genome-wide association mapping in A. thaHana and other species with similar patterns of variation. The rate of faase positives differed strongly between traits, with more disial traits showing the highest rate. However, the false positive rates were aiways substantial regardless of the trait, hkjhHghtirig the necessity of ars appropriate genomic control in association studies. Copyright: