You may have met your husband or wife by accident, but it seems that the term soul mate is true after all. You and your partner may have been destined to be together since birth because you likely have DNA that is similar to each other. A new study suggests that you may not have chosen your partner by chance. Instead, you may have picked him or her because you share similar genetic profiles.
For the study "Genetic and educational assortative mating among U.S. adults" published in the journal Proceedings of the National Academy of Sciences on May 19, a team of researchers used genomic data from the Health and Retirement Study to analyze the genomes of more than 800 couples.
By using 1.7 million single-nucleotide polymorphisms, a type of genetic variation, in each of the subjects' genomes, the researchers assessed the genetic similarity of married couples and found that their DNA have fewer differences than with randomly selected individuals, which means that married individuals tend to have similar DNA.
One reason why people who have similar genes end up together is that they have more chances to meet and mate, said study author Benjamin Domingue, from the Institute of Behavioral Science at the University of Colorado-Boulder.
Findings of the study also help explain why people tend to marry somebody of the same ethnicity or somebody they share similar characteristics and interests with. People, for instance, more often set their eyes on someone who has similar physical traits. Tall people are more often attracted to individuals of similar height and not to somebody short. Musically inclined individuals, on the other hand, are drawn to people who love to sing or are able to play musical instruments well and a similarity in DNA may have something to do with all of these.
"It's well-known that people marry folks who are like them," said Domingue. "But there's been a question about whether we mate at random with respect to genetics."
The likelihood of marrying someone who shares the same genetic similarities, however, is slimmer than the odds of marrying someone with the same level of education. The researchers said that the weight of genetic similarity only accounts for about a third of educational similarity when it comes to chances of marriage.
"We find that spouses are more genetically similar than two individuals chosen at random, but this similarity is at most one-third the magnitude of educational similarity," Domingue and colleagues wrote.