These oxytocin genes may influence number of friends

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New research links higher expression of two genes that regulate the release of oxytocin with greater friendliness and social skills among young adults.

Oxytocin is the paramount social hormone in humans, and is involved in primary social behaviors such as pair-bonding, mating, and child-rearing, as well as more sophisticated behaviors such as empathy, trust, and generosity.

Researchers at the National University of Singapore studied over 1,300 healthy young Chinese adults in Singapore in a non-clinical setting. They investigated the correlation between the expression of the CD38 gene and CD157 gene sequence, both of which have been implicated in autism studies, and an individual’s social skills as captured by three different questionnaires. The questionnaires evaluated the importance of and interest in friendships, as well as number of close friends/confidants.

“We believe that studying the expression of genes captures more information than simple structural studies of DNA sequence since it is the expression of genes that ultimately determine how a gene impacts our traits,” says Professor Richard Ebstein.

“Oxytocin plays an important role in these behaviors so it made good sense to our team to study the oxytocin network in relation to social skills important for friendships.”

The results from the study show that participants with higher expression of CD38 have more close friends, and this association was observed more prevalently among the male participants.

“Male participants with the higher gene expressions displayed greater sociality such as preferring activities involving other people over being alone, better communication, and empathy-related skills compared to the other participants.

“Meanwhile, participants with lower CD38 expression reported less social skills such as difficulty in “reading between the lines” or engaging less in social chitchat, and tend to have fewer friends,” says Anne Chong of the psychology department at NUS Faculty of Arts and Social Sciences. She is the first author of the study in Psychoneuroendocrinology

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Interestingly, the researchers found that a variation in the CD157 gene sequence that was more common in autism cases in a Japanese study was also associated with the participants’ innate interest in socializing and building relationships.

The evidence suggest that oxytocin, and the CD38 and CD157 genes that govern its release, contribute to individual differences in social skills from one extreme of intense social involvement (i.e. many good friendships and good relationships with peers) to the other extreme of avoiding social contacts with other people that is one of the characteristics of autism. The researchers note that the majority of people are in between the two extremes.

The researchers found that higher expression of the CD38 gene and differences in the CD157 gene sequence account for 14 percent of the variance in social skills in the general population.

“Moreover, while expressed genes can influence behaviors, our own experiences can influence the expression of genes in return. So, whether the genes are expressed to impact our behaviors or not, depend a lot on our social environments. For most people, being in healthy social environments, such as having loving and supportive families, friends, and colleagues, would most likely lessen the effects from disadvantageous genes,” says Chong.

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The findings contribute to possible future intervention therapies or treatments for individuals with special needs.

For instance, while there is already considerable research interest in using oxytocin therapy to improve the social skills of individuals with autism, the results so far have been mixed. The findings in this study point to an alternative research direction towards treatments based on new drugs that may mimic or enhance the functions of the CD38 and CD157 genes.

The researchers note however that this line of research has yet to be explored.

Source: National University of Singapore