Edinburgh, Scotland, United Kingdom - TAIR

Genome-wide association study of 100+
phenotypes in a common set of Arabidopsis
thaliana inbred lines
Arabidopsis thaliana is ideally suited for genome-wide association (GWA) studies
in that it naturally occurs as inbred lines, which can be genotyped once and
phenotyped repeatedly. We demonstrate the power of this approach by carrying
out a GWA study of 107 different phenotypes in a common set of 96-192 inbred
lines (the number of lines varies between phenotypes) genotyped for 250,000
SNPs using a custom Affymetrix chip. The results varied considerably between
phenotypes. A minority yielded unambiguous results in the form of distinct,
obviously significant associations, usually corresponding to single genes, and
often to a priori candidates. The majority of phenotypes, however, yielded results
that were harder to interpret because the combination of complex genetics and
confounding by population structure made it difficult to distinguish true from false
associations. A priori candidates are strongly overrepresented among these
associations as well. Our results are dramatically different from the results of
human GWA studies in that we identify a large number of loci with major effect
size, and that we often explain a considerable fraction of the phenotypic
variation. Our study clearly demonstrates the feasibility of GWA studies in A.
thaliana, and suggests that the approach will be appropriate for many other
organisms.
38
L13
Friday 09:00 - 09:30
Natural Variation
Magnus Nordborg
Gregor Mendel Institute
Dr Bohr-Gasse 3
030 Vienna
Austria