to standing genetic variation for these traits. As the current data set primarily consists of SNPs with MAF >0.01, rare (causal) variants are generally poorly tagged which, in turn, would explain some of the remaining heritability. Plausible arguments can be made that neuroticism and extraversion are correlated with fitness: mental disorders that are related to, or at the extreme end of, neuroticism and extraversion personality domains are associated with lower fertility, because of, for example, higher mortality rates and reduced mating opportunities.59, 60 Correlations between fitness and personality domains neuroticism and extraversion, however, are likely to be very low.
