The role of dopamine transporter (SLC6A3) and dopamine D2 receptor/ankyrin repeat and kinase domain containing 1 (DRD2/ANKK1) gene polymorphisms in personality traits

Variations in personality traits are caused by interactions between multiple genes of small effect and environmental factors. To date, gender- and ethnicity-specific variations in personality have been established. In the present study, we aimed to test: 1) the effects of four polymorphisms of dopamine system genes: ANKK1/DRD2 Taq1A, DRD2 rs6275, SLC6A3 40-bp VNTR and rs27072, on personality traits; 2) whether these effects differ between men and women and between Russians and Tatars. A sample of 652 healthy individuals (222 men and 430 women) of Caucasian origin (233 Russians and 419 Tatars) from Russia was subjected to personality traits assessment with Eysenck Personality Inventory (EPI) and Temperament and Character Inventory-125 (TCI-125). The associations between each personality trait and polymorphisms were assessed with regression models adjusted for gender and ethnicity. There were significant effects of ANKK1/DRD2 Taq1A on Neuroticism (p = 0.016) and of SLC6A3 rs27072 on Persistence (p = 0.021) in both genders. The association between ANKK1/DRD2 Taq1A A2/A2-genotype and higher Novelty Seeking and lower Reward Dependence was shown in men only (p for gender interaction = 0.018). In women only, there was a significant association between SLC6A3 10R*G-haplotype and higher Persistence (p = 0.002). Our findings provide evidence for a modifying effect of gender on the associations between dopamine system genes and approach-related traits (in men) and Persistence (in women).

Research highlights
► ANKK1 gene-by-gender interaction effects on Novelty Seeking and Reward Dependence.
► Association of ANKK1 A1-allele with lower NS and higher RD was indicated in men only.
► Association of SLC6A3 10R*G-haplotype and higher Persistence in women.