Author Date

2019-08-07

Degree Name

BS

Department

Psychology

College

Family, Home, and Social Sciences

Defense Date

2019-06-07

Publication Date

2019-08-07

First Faculty Advisor

Dr. J. Dee Higley

First Faculty Reader

Dr. Becky Lundwall

Honors Coordinator

Dr. Bruce Brown

Keywords

Oxytocin Receptor, Serotonin Transporter, Social Behavior, Rhesus Macaque, Primate Model, Genes

Abstract

Studies suggest that sociality plays a major role in physical and mental health, with loneliness, hostility, and aggression contributing to ill health. Genetic variation functions as a foundational basis for positive sociality, as well as antisocial behaviors such as social alienation and aggression. It is widely believed that the central serotonin and oxytocin systems are two neurotransmitter systems that play important roles in sociality and antisocial behavior. In this study, we investigate the genetic impact of the serotonin transporter gene (SERT) and a recently discovered oxytocin receptor (OXTR) gene on social isolation and antisocial behavior using a rhesus monkey model (Macaca mulatta). Blood samples were obtained from N = 127 rhesus monkeys (55 males, 72 females), and DNA was extracted and SERT and OXTR genotypes were characterized. As young adults (M = 6.23 years), the monkeys’ behaviors that characterize social affiliation, social isolation and aggression were recorded four times, randomly distributed over a month by trained observers using 300-second observations. Results showed an association between the OXTR genotype and rates of giving aggression and receiving social displacements from other group members. Results from linear regressions showed a dose-dependent effect of the T-allele. With each increase in the number of T-alleles, subjects exhibited increasing rates of aggression and agonistic displacements. There was also a nearly significant association between SERT genotype and average number of close social partners. The results from linear regressions showed that for each increase in the number of s-alleles, subjects had fewer social partners when compared to subjects that were homozygous for the L-allele. These findings suggest that subjects possessing a T-allele on OXTR and subjects possessing a ­s-allele on SERT show evidence of diminished social affiliation and increased antisocial behaviors such as aggression. These findings show that the oxytocin and serotonin systems influence social alienation and antisocial behaviors such as aggression. To the extent that these finding generalize to humans, they suggest potential etiological mechanisms of sociobehavioral disorders such as childhood aggression, conduct disorder, antisocial behavior, and possibly autism and schizophrenia.

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