A new study has revealed that your genes could influence who you make friends with.
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SYDNEY: It is not just shared interests that link friends together, but also their genes, according to researchers interested in the genetic basis of friendships.
The identification of genetic patterns within social networks throws new light on the various factors that influence friend choice.
“This is a first step towards understanding the biology of ‘chemistry’ - that feeling you have about a person that you will like or dislike them. We may choose our friends not just because of the social features we consciously notice about them, but because of the biological features we unconsciously notice”, said lead author James Fowler of the University of California, San Diego.
Birds of a feather
Amongst animals, humans are unusual in that we form long-term, non-reproductive relationships, otherwise known as friendships, with individuals with whom we are not necessarily closely related.
Although we tend to forge friendships with people with similar characteristics to us, the genetic consequences of these associations are largely unknown.
With their latest research, published in the Proceedings of the National Academy of Sciences, Fowler and his co-authors provide evidence that the formation of non-reproductive unions can result in genetic structuring across a population.
Strong correlation
Utilising data collected in two independent health studies in the U.S., the authors compared variance in six genes across more than one thousand friendship pairs. To control for population stratification - the tendency of people to have similar genotypes because they befriend others in the same geographical area - information on ethnicity and sibling genotype was included in the analysis.
Of the six genes analysed, two exhibited a strong correlation between their expression and the likelihood of individuals to be friends.
Individuals carrying a gene associated with alcoholism, DDR2, were more likely to befriend other DDR2-positive peers, while DDR2-negative individuals formed friendships with those who lacked the gene.
Opposites attract
Conversely, another gene gave unexpected credence to the adage ‘opposites attract’, with people carrying a gene associated with an open personality type, CYP2A6, tending to make friends with individuals who lacked the gene.
The genes that bind, really?
The first sentence of the article. "It is not just shared interests that link friends together". I would say it IS predominantly shared interests that link people. People with a specific 'rare' gene expressions will group with others that also have that expression (due to a shared interest). But for the majority of people with less differentiating expressions their friendships (non sexual) will not be so guided and their chances of hooking up will be more greatly influenced by other factors and random opportunities. That may be why 4 out of the 6 genes examined showed no such friend groupings.