“Replicability and Robustness of Genome-Wide-Association Studies for Behavioral Traits”, Cornelius A. Rietveld, Dalton Conley, Nicholas Eriksson, Tõnu Esko, Sarah E. Medland, Anna A. E. Vinkhuyzen, Jian Yang, Jason D. Boardman, Christopher F. Chabris, Christopher T. Dawes, Benjamin W. Domingue, David A. Hinds, Magnus Johannesson, Amy K. Kiefer, David Laibson, Patrik K. E. Magnusson, Joanna L. Mountain, Sven Oskarsson, Olga Rostapshova, Alexander Teumer, Joyce Y. Tung, Peter M. Visscher, Daniel J. Benjamin, David Cesarini, Philipp Koellinger2014 (, ; backlinks; similar)⁠:

A recent genome-wide-association study [Rietveld et al 2013] of educational attainment identified 3 single-nucleotide polymorphisms (SNPs) whose associations, despite their small effect sizes (each R2 ≈ 0.02%), reached genome-wide statistical-significance (p < 5 × 10−8) in a large discovery sample and were replicated in an independent sample (p < 0.05). The study also reported associations between educational attainment & indices of SNPs called “polygenic scores”.

In 3 studies, we evaluated the robustness of these findings: Study 1 showed that the associations with all 3 SNPs were replicated in another large (n = 34,428) independent sample. We also found that the scores remained predictive (R2 ≈ 2%) in regressions with stringent controls for population stratification (Study 2) and in new within-family analyses (Study 3).

Our results show that large and therefore well-powered genome-wide-association studies can identify replicable genetic associations with behavioral traits. The small effect sizes of individual SNPs are likely to be a major contributing factor explaining the striking contrast between our results and the disappointing replication record of most candidate-gene studies.