The present study provides the first GWA results for all five dimensions of personality, as measured by the Revised NEO Personality Inventory (NEO-PI-R)(38). This study is part of the SardiNIA project (3), which has targeted a highly interrelated population from the isolated Ogliastra region of Sardinia, Italy (3). Common variants associated with several complex traits (8, 11, 39-41) have been successfully identified in this sample, and the results replicated across diverse populations. The studies of population isolates are advantageous because these groups are highly homogeneous, reducing the risk of spurious associations due to population stratification. Furthermore, population isolates have more extensive stretches of linkage disequilibrium (LD) compared to outbred populations (42). The wider level of LD increases the genome-wide coverage of standard SNP arrays in cohorts such as the Sardinian. The advantages of having reduced variability in a founder population come at the cost of lower power to replicate the effects in more heterogeneous populations. However, several findings from this Sardinian cohort have been replicated in other populations (8, 11, 39-41).
