They say that “opposites attract”. However, researchers have found that a different piece of wisdom is more accurate. “Birds of a feather flock together”. It turns out that people are unconsciously selecting romantic partners whom they share some genetic similarity with.
The report was published in the journal Proceedings of the National Academy of Science. Researchers were gathering data that could be used to further explain assortative mating.
Assortative mating is a nonrandom mating in which individuals with similar genotypes or phenotypes choose to mate with one another more frequently than what would be expected under a random mating pattern. In “plain English”, it means that people seek out mates that have similar physical traits to themselves, or that have similar genetics.
The researchers analyzed genetic data from 825 non-Hispanic white Americans who participated in the U.S. Health and Retirement Study. Next, they compared the similarity of the DNA of married couples with the similarity of random individuals who were not coupled. The researchers looked at opposite-sex couples, only. They found that people tend to pick spouses whose genetic profile is similar to their own.
This is not the first study to come to that conclusion. The Framingham Heart Study found that married people have more similar DNA fragments than random pairs of people do. In short, this means that your parents probably have some genetic similarity to each other.
There are plenty of other ways that people engage in assortative mating. People also tend to select a romantic partner who is similar to themselves in other ways. They both have the same amount of education, or both belong to the same social class. People might choose a partner who is the same race that they are, or who has the same body weight. Some choose based on intelligence or geographical proximity.
Keep in mind that this does not mean that genetics are the biggest reason why two people became a couple. It is just one factor that influences that selection. Other questions still need to be answered. It might be possible that people’s genes are a factor that puts people into certain environments. Could the reason why people pick a mate who has similar genetics be because that is who is around to choose from?
The researchers summed up their report this way. “Of even greater value would be understanding the quantity of nonrandom mating that there is genetically with respect to the trait and how these associations have changed over time.”
Image by Leon Brocard on Flickr.
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