Journal of Undergraduate Research


physical and mental health, rhesus macaques, oxytocin and social affiliation, genetics


Family, Home, and Social Sciences




Studies suggest that social relationships play a critical role in physical and mental health1, with effect sizes similar to that seen for smoking and alcohol abuse. Those experiencing real or perceived social isolation show higher rates of mortality3, while those with stronger social relationships show decreased rates of mortality4. Also, genetic variation has been associated with the degree of individual sociability2. The serotonin (5-HT) and oxytocin (OT) systems are believed to influence social behavior6,2. The serotonin transporter (SERT) gene codes for efficiency of the serotonin system, with the long (L) allele associated with greater efficiency, when compared to the short (s) allele. A naturally-occurring gene variation of the oxytocin receptor (OXTR) gene leads to increased sensitivity to OT, when compared to the ancestral gene. Thus, the allele variation (A) leads to increased rates of OT receptor binding, when compared to the ancestral allele (G). Due to inherent difficulties in understanding the impact of the SERT and OXTR genotypes on behavioral outcomes in humans, a rhesus macaque (Macaca mulatta) model is used to investigate genetic influences on behavioral outcomes, as they possess many social and genetic similarities to humans7, including orthologous SERT genotypes and parallel OXTR genetic variability. Rhesus monkeys are ideally suited to model genetic effects due to their environment that can be easily controlled and maintained. Importantly, rhesus monkeys are commonly used as experimental models to investigate loneliness5 and social behaviors. Hypothesis 1: Subjects homozygous for the L allele of SERT gene will exhibit an increased degree of affiliative behavior when compared to subjects possessing an s allele. Hypothesis 2: Subjects homozygous for the A allele of the OXTR genotype will exhibit an increased degree of affiliative behaviors when compared to subjects possessing a G allele.

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Psychology Commons