Having a double dose of a gene that boosts levels of serotonin appears to increase students’ chances of romance
Chinese scientists claim to have found a gene variant that nudges up the odds of university students being in romantic relationships.
They found that students who inherited two copies of the gene type were more likely to have a romantic partner than other students. The researchers put the effect down to the influence that the gene variant has on a person’s mood and mental wellbeing through the brain chemical serotonin.
The team at Peking University say the finding is the first direct evidence that genetic factors play a role in the formation of relationships, though personality, appearance, education and even wealth are all affected by genetics too.
The scientists focused on a gene called 5-HTA1, which affects levels of the mood hormone, serotonin. One version of the gene, the C variant, leads to higher levels of serotonin than the other form, the G variant. Everyone has two copies of the gene, and inherits two of the C variant, two of the G variant, or one of each, depending on the type passed down from each parent.
Tests on 579 Han Chinese students revealed that half of those who inherited two copies of the C variant – one from each parent – were in relationships. But students who carried one or two copies of the G variant had only a 40% chance of being in a relationship. The effect was small, but statistically significant.
Writing in the journal Scientific Reports, Xiaolin Zhou at Peking University says that people who inherit the G variant of the gene are more likely to be neurotic and develop depression. “As pessimism and neuroticism are detrimental to the formation, quality and stability of relationships, this connection between the G [variant] and psychological disorders might decrease carriers’ dating opportunities or lead to romantic relationship failure,” he writes.
But the strand of DNA in question is far from being a love gene. The scientists’ analysis found that among the students who took part, the gene explained only 1.4% of the difference in likelihood of being single or in a relationship.
“Whilst genetic factors will inevitably influence relationship status, this specific marker accounts for only a very small part of that, and on its own has little bearing on whether an individual is in a relationship or not,” said Thalia Eley, professor of developmental behavioural genetics at Kings College London.
The scientists warn that the gene might not stand out at all in other populations. In the 1980s, the authors write, students at Chinese universities were banned from having romantic relationships. But the group of students who took part in the study arrived at college after the ban lifted, and were fairly free to start up relationships. Later in life, family and social pressures could overwhelm the influence of their genetic makeup.
“It’s provocative and really interesting,” said Aleksandr Kogan, a psychologist at Cambridge University. “In human social behaviour, it’s so unusual for something to make such a big difference, especially a single variant, unless it’s a disease where you have a serious abnormality.”
“A lot of things affect whether you’re in a relationship or not. People break up under a lot of different circumstances. So you wouldn’t expect everyone who is CC to be in a relationship. But 50% of them are, compared with only 40% of the others, and that’s quite a gap.”
This article was written by Ian Sample, science editor, for theguardian.com on Thursday 20th November 2014 14.22 Europe/Londonguardian.co.uk © Guardian News and Media Limited 2010