Your genes and those of your friends are likely to be more similar than yours compared to a complete stranger, Add Health data shows. That’s not because we actively seek out people with similar genes—rather, our social environment and background naturally result in our ending up more likely to become friends with people who are similar to us. This is an important development because while geneticists have long considered the effects of our genome on traits like educational attainment, we now know that we also need to consider the reverse effect.
The equation grew more interesting when the researchers compared schoolmates’ genomes. Classmates were about half as genetically similar as friends and significantly more similar than unaffiliated individuals — which suggests that a shared environment and background may account for a good chunk of the genetic likeness observed among friends, Domingue explains. That, in turn, underscores how closely genetics and social circumstances are linked.
Read the story in TIME: Friends Are More Similar Genetically Than Strangers, Study Says by Jamie Ducharme, January 12, 2018.