Social epigenetics
The genetic basis of the difficulties of social interactions
Sergey Syrov, XXII CENTURY, based on the materials of the University of Georgia: Silencing of gene affects people's social lives, study shows
A team of psychologists from the University of Georgia, USA, found that turning off a certain gene can affect a person's social behavior, including the ability to form healthy relationships and recognize the emotional states of other people.
In an article published on June 20 in the journal Proceedings of the National Academy of Sciences (Haas et al., Epigenetic modification of OXT and human sociability), it is reported that the methylation process, which can interfere with the expression of certain genes, also affects the OXT gene. This gene encodes a protein – the hormone oxytocin, the one that is associated with a wide range of manifestations of social behavior in humans and other mammals.
"Methylation limits gene expression,– says Brian W. Haas, lead author of the study. – An increase in methylation usually corresponds to a decrease in gene expression, this affects how functional a particular gene is.
When methylation increases relative to the OXT gene, this leads to a decrease in the activity of this gene. Our research shows that this can have a profound effect on social behavior."
Haas and his colleagues took saliva samples from more than 120 study participants and conducted genetic tests to determine the level of methylation of the OXT gene. Participants also passed a series of tests to assess both social skills and structural and functional features of the brain.
It was found that participants with a large methylation of the OXT gene and a corresponding lower level of expression of this gene showed impaired understanding of emotional facial expressions, they usually have problems in relationships with loved ones.
At one stage of the study, participants were shown short video clips in which a person depicts an emotion – a face with a neutral expression gradually transforms into an emotional one. The participant's task was to press the button as soon as he recognized the type of emotion being demonstrated.
"Participants with more methylation of the gene were less accurate in describing the emotional states of the people they saw," says Haas. "This is a typical trait associated, for example, with autism."
The scientists also used functional magnetic resonance imaging, a technology that measures brain activity by observing changes in the oxygen content in the bloodstream, which makes it possible to determine which areas in the human brain are activated when performing various tasks. It was found that increased methylation of the OXT gene reduces the neural activity of the brain in regions associated with socio-cognitive processing.
These participants also showed a decrease in the amount of gray matter in the brain area, which is important in the task of identifying faces and social behavior. It is called the fusiform gyrus.
"All our tests show that the OXT gene plays an important role in social behavior and brain function," concludes Haas.
Haas and his co-authors warn that the results of their work remain preliminary and much more needs to be done to more clearly define the role of oxytocin and the genes that control its production. He hopes that this research will one day lead to the creation of new effective procedures for the treatment of various social behavior disorders.
"Methylation is a dynamic process and the level of methylation can change throughout a person's life," says Haas, "But perhaps there will be drugs that will change the level of methylation and help people who have deviations in social cognition."
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22.06.2016