Possible associations of DRD2 and BDNF gene polymorphisms with certain personal traits of successful businessmen

Abstract

Background. The DRD2 and BDNF genes are localized on the same 11th chromosome and may be involved in a number of psychic manifestations of human behavior. Both the Taq1A polymorphism of the DRD2 gene and the Val66Met polymorphism of the BDNF gene are associated with aggressiveness, mental disorders, and high «novelty-seeking» scores. These gene variants likely exert epistatic or pleiotropic effect on manifestation of some psychological traits of an individual personality, which, in turn, may influence the choice of his/her type of activity. The aim of this study was to find associations of the Taq1A and Val66Met polymorphisms and frequencies of corresponding genotypes with definite personal traits and the choice of the type of activity. Methods. 94 people successfully engaged in business were interviewed with the Mini-Mult Psychological Inventory (MMPI), Zuckerman’s scale (SSS, sensation seeking scale) and scale of personality traits of the Big Five (TIPI). After that, alleles A1 and A2 of the DRD2 gene and alleles Val and Met of the BDNF gene were identified in their DNA samples using the PCR technique. Statistical methods were used to find significant associations between levels of personality trait manifestations and carriage of definite genotypes. Results. A2A2Val/Val homozygotes and A1/A2Val/Met diheterozygotes demonstrated the greatest need for sensation-seeking according to the Zuckerman’s SSS scale and also the maximal «Openness to experience» and the minimal «Extraversion» according to personality traits of the Big Five TIPI scale. The questions of the Mini-Mult test (MMPI) showed in creased predisposition to conflict for the A2/A2/Met+
combinations compared to the A2+/Val/Val genotypes. Despite this, the incidence of the A2/A2/Val/Met combination was significantly increased (1.5 times) whereas the incidence of the A2/A2Val/Val and A1/A2Val/Val genotypes was decreased compared to computed values. At the same time, carriers of this combination had average levels of «Sensation seeking» and «Openness to experience» (i.e., they were prone to a prudent risk) in combination with average «Extraversion» and «Conscientiousness». Such psychological traits are necessary for success in business.
Conclusions. The presence of significant associations between the genotype and the level of personality trait manifestation suggested the existence of genotype selection for this kind of activity.