The effect of DRD4 gene on violence tendency in athletes

This study aims to investigate the effect of the dopamine D4 receptor (DRD4) gene on violence tendency between athletes and non-athletes. A total of 328 volunteers participated in the study, 214 athletes between the ages of 16 and 32 who have been actively involved in sports for an average of 10.04 years and 114 randomly selected controls (sedentary). A personal information form was used as a data collection tool, and the "Violence Tendency Scale" developed by Göka, Bayat, and Türkçapar was used to determine the participants' levels of violence. DNA isolation and genotyping methods were used to examine the participants' DRD4 genotypes and alleles. SPSS 24 package program was used to analyze the data. Our findings reveal significant differences in certain DRD4 variable number tandem repeat genotypes and alleles between athlete and sedentary groups, particularly in the 2/4 and 4/4 genotypes and the 2R and 4R alleles (p < 0.05), while no meaningful differences were observed in other genotypes or alleles (p > 0.05). No significant associations were found between short- and long-repeat genotypes and demographic or background variables such as age, height, weight, gender, type of sport, athletic family history, and chronic illness (p > 0.05). However, a consistent and significant relationship emerged between athletes' reactions to referee decisions and opponents' illegal interventions and their history of aggressive behavior, including penalties for unsportsmanlike conduct and violent incidents throughout their sports careers (p < 0.05). The DRD4 gene may play a potential role in the tendency to violence. The results of this study provide important clues for understanding the biological basis of violence and preventing it.