More Americans Are Marrying Genetically Different Mates; Trend Could Result In Healthier Children

You may think opposites attract, but when it comes to choosing a mate, most opt for someone similar to themselves. So similar in fact, that they’re likely to be genetically related. According to a new study, mating patterns in the U.S. show most people not only picked a spouse from their own community, but also one that shared genetic similarity. However, the team noted that this trend is on its way out, and younger individuals are far more likely to pick romantic partners with different genetic backgrounds, something that could be better for their offspring.

A new study published online in Plos Genetics found that a previous pattern where people married genetically similar mates has resulted in many married couples sharing a surprisingly close genetic background. According to a press release, this trend means that certain populations have a genetic code that is so similar, it may even bias the results of genetic studies, like when a false positive is identified in gene regions associated with a particular condition. For example, the results showed that the correlation between spouse genetic ancestry was even greater than correlation in spouse age. However, this trend is on the way out, as each successive generation is less likely to choose a mate with the same ancestry as the generation before.

Read: Interracial Couples May Make Taller, Smarter Children Due To Greater Genetic Diversity: Study

For the study, the team looked specifically at genetic similarity between 879 spouses from three generations of white people who were involved in the Framingham Heart study, an ongoing study originally designed to study the heart health of residents in Framingham Massachusetts. According to the press release, results showed that individuals of Northern European, Southern European and Ashkenazi Jewish ancestry time and again preferred to choose spouses of the same background. Results also showed over the past 60 years, younger generations are less likely to choose genetically matched mates than their parents, a trend that was especially seen in those of Northern/Western and Southern European ancestry.

mixed race Fewer couples are choosing to marry someone from a similar genetic background. Photo Courtesy of Getty/ Cameron Spencer

This trend toward genetic diversity between mates may be a good thing; offspring with more genetic diversity have a greater chance of survival. From a biological standpoint, populations with less genetic diversity can't cope as well with environmental pressures, such as diseases. For example, according to the University of Utah, populations with high genetic diversity have a better chance of surviving sudden hardships, such as a unprecedented outbreak. These individuals will then reproduce and the population will survive.

Even on a smaller scale, research has shown that bigger differences in genetic diversity among parents tend to result in children who are taller and more intelligent. In addition, the same report also found that greater genetic diversity was also associated with better cognitive skills and higher levels of education, The Daily Mail reported.

Source: Sebro R, Peloso GN, Dupuis J, Risch NJ. Structured mating: Patterns and implications. Plos Genetics. 2017

See Also:

Genetic Analysis Of African Americans From African Diaspora And Great Migration Reveals Unique Ancestry, Origins

Did A Cultural Shift Influence Human Evolution? How Farming Might Have Changed Genetic Diversity

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