* Many people are not yet subscribed to the statslausanne mailing-list; please forward appropriately to your colleagues * Our next statistics forum for people interested in quantitative methods in biology and medicine will take place Thursday, 28 June at 11h00 in the Génopode Building in Dorigny (exact room still to be confirmed; there will be signs in any case once you enter the building). The speaker will be Zoltán Kutalik, from the Department of Medical Genetics, who will talk about "Estimating the invisible: Effect size distributions in genome-wide association studies". Abstract: Genome-wide association studies (GWAS) are conducted with the promise to discover novel genetic variants associated with diverse traits. For most traits, associated markers individually explain just a modest fraction of the phenotypic variation, but their number can well be in the hundreds. We developed a maximum likelihood method that allows us to infer the distribution of associated variants even when many of them were missed by chance. Compared to previous approaches, the novelty of our method is that it (a) does not require having an independent (unbiased) estimate of the effect sizes; (b) makes use of the complete distribution of P-values while allowing for the false discovery rate; (c) takes into account allelic heterogeneity and the SNP pruning strategy. We applied our method to the latest GWAS meta-analysis results of the GIANT consortium. It revealed that the observed P-values provide evidence for the existence of variants explaining several fold higher phenotypic variance than genome-wide significant SNPs. This methodology also enables us to predict the benefit of future GWA studies that aim to reveal more associated genetic markers via increased sample size. You can find more information about the forum on our web page at http://moodle.unil.ch/course/view.php?id=2729 Hope to see you there ! Frédéric