CREDIT: RYAN SNOOK (from Holden, 2008).The latest search for genetic variants that underlie differences in personality traits has drawn a blank (Verweij et al., 2010). The researchers conducted a genome-wide association study using personality ratings from Cloninger's temperament scales in a population of 5,117 Australian individuals:Participants' scores on Harm Avoidance, Novelty Seeking, Reward Dependence, and Persistence were tested for association with 1,252,387 genetic markers. We also performed gene-based association tests and biological pathway analyses. No genetic variants that significantly contribute to personality variation were identified, while our sample provides over 90% power to detect variants that explain only 1% of the trait variance. This indicates that individual common genetic variants of this size or greater do not contribute to personality trait variation, which has important implications regarding the genetic ...