Investigating the Genetic Diversity of DRD2 and OXTR Genes in the Iranian Population and Its Relationship with Personality Traits

By analyzing genetic polymorphisms in the genes of patients and control subjects, it is possible to find the correlation of these factors with the phenotypic variation as mental disorders to propose hypotheses about the possible mechanisms of specific diseases. Accordingly, in the present study, the role of oxytocin receptor and dopamine D2 receptor polymorphisms in the personality traits of optimistic, pessimistic and intermediate individuals was investigated. In this study, the polymorphism of DRD2 receptors and oxytocin receptor genes in saliva samples of Iranian volunteers was investigated. Accordingly, saliva samples were prepared from 90 individuals. The mental status of these individuals (optimistic, pessimistic and intermediate) was determined by a specialist physician. Then, the DNA of the sample was extracted and the presence or absence of the rs53576 polymorphism in the OXTR gene and the rs1800497 polymorphism in the DRD2 gene was examined using PCR reaction and sequencing. The results showed a significant association between the frequency of the rs53576 polymorphism in the OXTR gene and pessimism. In fact, the A allele in this polymorphism caused a 2.4-fold increase in pessimism in the studied individuals. However, no significant association was observed between the rs1800497 polymorphism and the traits of optimism and pessimism. Such studies require more detailed assessments such as brain scans, but due to the high cost of such tests, genetic studies can be used as the first step to confirm or reject the association of the polymorphism with the aforementioned trait.