Epigenetic modification of OXT and human sociability

Abstract

Across many mammalian species there exist genetic and biological systems that facilitate the tendency to be social. Oxytocin is a neuropeptide involved in social-approach behaviors in humans and others mammals. Although there exists a large, mounting body of evidence showing that oxytocin signaling genes are associated with human sociability, very little is currently known regarding the way the structural gene for oxytocin (OXT) confers individual differences in human sociability. In this study, we undertook a comprehensive approach to investigate the association between epigenetic modification of OXT via DNA methylation, and overt measures of social processing, including self-report, behavior, and brain function and structure. Genetic data were collected via saliva samples and analyzed to target and quantify DNA methylation across the promoter region of OXT. We observed a consistent pattern of results across sociability measures. People that exhibit lower OXT DNA methylation (presumably linked to higher OXT expression) display more secure attachment styles, improved ability to recognize emotional facial expressions, greater superior temporal sulcus activity during two social-cognitive functional MRI tasks, and larger fusiform gyrus gray matter volume than people that exhibit higher OXT DNA methylation. These findings provide empirical evidence that epigenetic modification of OXT is linked to several overt measures of sociability in humans and serve to advance progress in translational social neuroscience research toward a better understanding of the evolutionary and genetic basis of normal and abnormal human sociability.ociability is a central feature of the human species. Through one perspective, the complex array of human social-cognition and behavior serves to differentiate humans from other animals. However, there exist several core elemental components of the human sociobiological system that are present across many animal species, which may have remained relatively conserved throughout recent evolutionary history (1). Elucidating the genetic and biological substrates of social behavior serves to advance the way basic human nature is understood and improves the way genetic and biological markers can be used to prevent, diagnose, and treat people with impairments in social cognition and behavior.Oxytocin is a neurohypophysial peptide synthesized in the hypothalamus in the brain, linked to a wide range of social behaviors in humans and other mammals. Administration of oxytocin in humans is associated with changes in social-approach behaviors, such as trust (2) and personal proximity (3). This evidence has motivated the search for genes within the oxytocin system that confer individual differences in social behavior and cognition. A burgeoning body of evidence highlights the role of several key genes within the oxytocin signaling pathway linked to sociability, including the oxytocin receptor gene (OXTR), CD38, and the structural gene for oxytocin (OXT) (4). Although mounting data strongly support the role of ...

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