Friendliness: It’s in the Genes

You may be as friendly as your Genes.

Friendliness: It’s in the Genes
The two genes regulate Oxytocin, considered the supreme human social hormone, and are associated with a young adult's social skills and number of friends. Credit: NUS researchers

Some people enjoy going to parties, doing conferences, talking in public. They have the inclination of friendliness and to socialize more. On the other hand, some people prefer solitude. Such kind of people like their own company more than their friends. But why this happens?

According to scientists, it may be because of two genes that regulate oxytocin hormone in our bodies.

NUS scientists found that a higher expression of the CD38 gene and the presence of differences in the CD157 gene sequence are associated with a person’s social skills. They discovered how the expression of CD38 in the participants and the sequence changes of CD157 gene correlated with their social skills.

For the study, scientists recruited 1,300 Chinese young adults in Singapore. They then evaluated participants via questionnaires which evaluated their capacity of friendliness and the quality of their friendships.

Mainly, Oxytocin is responsible for many social behaviors including pair-bonding, mating, child-rearing, empathy, trust, and generosity.

Scientists found that the genes CD157 and CD38 regulate the release of oxytocin into the body. They found Oxytocin network in relation to social skills important for friendships.

Professor Richard Ebstein said, “Many gene studies often only focus on the structural changes in the gene sequences and how that could affect a particular characteristic of a disease. But, we believe that studying gene expression including how much of the gene is produced in the body would capture more information than simple structural studies on DNA sequences.”

“It is the expression of genes that ultimately determine how a gene impacts our traits.”

The study shows that a higher expression of CD38 is associated with friendliness, especially in male participants. It also suggests a change in the sequence of CD157 was associated with the participants’ interest in socializing and building relationships. Actually, it correlates with increased expression of CD38 in the bloodstream and the levels of oxytocin in the body.

Recent PhD graduate Dr Anne Chong said, “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.”

“The higher expression of CD38 and the structural changes of CD157 would explain about 14 per cent of the variance in social skills in the general population. This number is a far cry from the two percent that studies only focusing on structural changes usually explain.”

Prof Ebstein said, “In our study, we see that an individual’s genetic makeup could only go so far as predicting one’s social predisposition but does not necessarily trigger the trait since, in the end, it is the expression of a gene that determines so.”

“This knowledge would be helpful in coming up with future intervention therapies or targeted treatments to achieve desired outcomes for individuals with special needs.”