The true genetic architecture underlying variation in personality is of course unknown, but as with other complex polygenic phenotypes, causal loci are likely represented by a mixture of common variants of small effect and rare variants some of which could have larger effect. Height is a classic polygenic phenotype; a recent meta-analysis of ∼180K persons has demonstrated that 10.5% of the phenotypic variation in height can be explained by 180 associated loci.38 Although our study is much smaller, it is worth noting that our prediction analysis accounted for, at most, only 0.28% of the phenotypic variability in temperament scales.
