Oxytocin is Greek for “swift birth,” but this hormone — which helps induce labor and promote lactation — has garnered many other names in the media, from the “cuddle chemical” to the “morality molecule.” The “pro-social” effects of oxytocin on humans has become the subject of innumerable studies of varied reliability that have investigated impacts on trust, generosity, and empathy. But it’s clear that this hormone, which is released into the bloodstream by the pituitary gland, impacts social bonding.
As oxytocin flows through the blood, it communicates with cells by specifically interacting with the oxytocin receptor — a protein on the surface of cells that catches this hormone as it passes by. Numerous studies link rs53576, a SNP in the oxytocin receptor gene called OXTR, to emotional and social processes.
Studies have suggested that people who are either AA or AG at rs53576 are more sensitive to stress and have reduced social skills compared to individuals who are GG. A recent study published by Shimon Saphire-Bernstein at UCLA provided evidence that people who carry the A version of rs53576 are less optimistic and have lower self-esteem. In addition, brain scans have suggested that AA or AG individuals are less responsive to social cues than GG people.
Although not proven, there is also some evidence that people who carry the A version of rs53576 are at increased risk for autism, a disorder characterized by impaired social interaction and communication. Oxytocin is currently being used experimentally to treat children with autism (read more about this here and here).
A new study conducted by Aleksander Kogan at the University of Toronto suggests that people with at least one A at rs53576 are readily perceived by others as being less prosocial than GG individuals. A prosocial behavior is any voluntary behavior intended to benefit another person, for instance showing empathy. Kogan and colleagues recruited “observers” to view “subjects” listening to their romantic partners talk about going through a tough time. After only 20 seconds of watching, observers determined how pro-social the subject was. AA and AG individuals were judged to be less pro-social and displayed fewer nonverbal cues — head nods and smiles — compared to GG people. The study suggested that the association between rs53576 and prosociality was stronger for men, but also true for women.
Even though these findings resonate with numerous studies linking rs53576 to prosocial behavior and empathy, they should be considered as preliminary since the study was carried out with a limited number of participants — 23 to be exact and all of European ethnicity. Some geneticists have suggested that this sample size is simply too small to provide meaningful information, but it can also be argued that a very large sample wasn’t necessary because only a single, well-studied SNP was investigated.
Says Kogan, “Our study benefits from over a dozen studies that have reported findings very consistent with ours using much larger samples from the same general population — Caucasians in the United States.” He also adds, “We are now attempting much larger replication studies.”
Although 23andMe occasionally reports findings from studies with less than 100 cases (a one-star report on our website), we are more confident about data generated with larger sample sizes. A full description of our sample size requirements can be found in our white paper entitled Guidelines on Vetting Genetic Associations.
SNPwatch gives you the latest news about research linking various traits and conditions to individual genetic variations. These studies are exciting because they offer a glimpse into how genetics may affect our bodies and health; but in most cases, more work is needed before this research can provide information of value to individuals. For that reason it is important to remember that like all information we provide, the studies we describe in SNPwatch are for research and educational purposes only. SNPwatch is not intended to be a substitute for professional medical advice; you should always seek the advice of your physician or other appropriate healthcare professional with any questions you may have regarding diagnosis, cure, treatment or prevention of any disease or other medical condition.