Below are excerpts from a NewScientist article by Priya Shetty titled "Monogamy gene found in people." The entire article can be read here.
There has been speculation about the role of the hormone vasopressin in humans ever since we discovered that variations in where receptors for the hormone are expressed makes prairie voles strictly monogamous but meadow voles promiscuous; vasopressin is related to the "cuddle chemical" oxytocin. Now it seems variations in a section of the gene coding for a vasopressin receptor in people help to determine whether men are serial commitment-phobes or devoted husbands.
Hasse Walum at the Karolinska Institute in Stockholm, Sweden, and colleagues looked at the various forms of the gene coding for a vasopressin receptor in 552 Swedish people, who were all in heterosexual partnerships. The researchers also investigated the quality of their relationships.
They found that variation in a section of the gene called RS3 334 was linked to how men bond with their partners. Men can have none, one or two copies of the RS3 334 section, and the higher the number of copies, the worse men scored on a measure of pair bonding.
Not only that, men with two copies of RS3 334 were more likely to be unmarried than men with one or none, and if they were married, they were twice as likely to have a marital crisis.
RS3 334's social effects extend beyond bonding in couples. Earlier this year, the same gene section was shown to affect signalling in people's amygdalas, linked to trust. Another study found that people with autism, which is characterised by unusual social behaviour, often have multiple copies of RS3 334.
Walum's colleague Paul Lichtenstein says the team's next task is to test how a nasal vasopressin spray affects altruism and jealousy.