A study, published by Walum and colleagues (2008), has identified a gene that could promote monogamy in humans. And men who inherit a particular variant of this gene are prone to marital woes and commitment problems according to the research.
The research, by a Swedish team from the Karolinska Institute, examined DNA from a big research project called “The Twin and Offspring Study” which analyses genetic and behavioral data from more than 550 twins and their partners or spouses.
The people who participated in the study were asked a series of questions about their relationships and this was compared to their DNA. All the twins were in long term relationships and had children.
The gene in question is AVPR1A and it codes for a protein called Vasopressin, which is a brain hormone. The same hormone has also been shown to affect monogamy in voles.
In the study, researchers found that men who had one 334 allelic version of the gene were likely to be scored lower by their partners for the strength of the relationship bond. They were also less likely to be married.
Men who had 2 copies of the 334 allele were inclined to remain single, but if they were to get married they would be twice as more inclined to have marital crisis than those men having only one or no copy of the 334 allele.
In addition, the study showed that women married or living with men who had 1 or 2 copies of 334 were less satisfied in their relationship than women married to men without 334.
Is cheating genetic?
That's the BIG question, and the answer is not a simple one to give. Just because a man may have a particular variant of the AVPR1A gene does not necessarily mean he will have trouble in his relationships. There are so many cultural, psychological and environmental factors that also have a bearing on relationships. Perhaps the gene interacts with the environment in some way to produce the behavior?
Walum and his colleagues would like their work to be replicated by another team, before any firm conclusions can be drawn. One possible avenue for research will be to look at Vasopressin and how it works, especially as it was carried by 40 per cent of men in the study.
Walum eat al. (2008). Genetic variation in the vasopressin receptor 1a gene (AVPR1A) associates with pair-bonding behavior in humans. PNAS Early Edition, 2-5 September 2008.