Genes matter: People marry mates with similar DNA but different immune systems

a e z
Wedding. (Credit: Walter/Flickr)

Humans love cliches, and journalists are no exception. But when it comes to human mating, sociologists have known for a long time that opposites don’t actually attract. People pick their mates based more often on the traits they share rather than those that make them different.

As Stephanie Pappas at LiveScience reports, similar mate traits come from across the spectrum of human experience:

When it comes to marriage, the adage “birds of a feather flock together” is more on-point than the idea that opposites attract. Many studies have found that people tend to marry others who are similar to them in education, social class, race and even body weight. The phenomenon is called assortative mating.

Behavioral scientist Benjamin W. Domingue and his colleagues attempted to find out whether this assortative mating happens at the genetic level. They analyzed data from nearly two million spots in each person’s genome and compared them among couples or from a random pair. The couples were more genetically similar than a random pair of people in the study, but the effect they found wasn’t very big. In fact, it was just a third of the size of the effect you find when looking at similarity of education level in couples. The education-based assortative mating effect is the most widely studied mating effect in the scientific literature.

Interestingly, the study seems to contradict another well documented mating related behavior. People often pick out partners who have different, complementary immunity, or at least a subset of the immune system defined by a set of genes on chromosome six. How is this possible if mates are overall genetically similar? The authors suggest different evolutionary effects could be acting on different parts of the genome:

Such region-specific, negative-assortative-mating dynamic may serve to depress overall (positive) GAM estimates. Thus, it may behoove future researchers to break apart the genome into parts that are relevant to specific pathways or processes that may be under different selective pressures to see if genome-wide GAM estimates mask a mixture of strong positive and negative dynamics with respect to different dimensions.

This was an early study. The analysis only included white, heterosexual, married couples. This opens up a lot of room for further investigation. But, if the effect holds after more testing, it could have a lot of significance for our understandings of genetics and populations writes Alex Berezow at RealClearScience:

The extent of nonrandom mating is not properly accounted for in many epidemiological and population genetics analyses. That means previous investigations into how human populations evolve, as well as how genes influence socioeconomic outcomes, may not be entirely accurate.


Related article:  Scientists just calculated the total amount of DNA there is on Earth

Additional Resources:

Outbreak Daily Digest
Biotech Facts & Fallacies
Talking Biotech
Genetics Unzipped
can you boost your immune system to prevent coronavirus spread x

Video: How to boost your immune system to guard against COVID and other illnesses

Scientists have recently developed ways to measure your immune age. Fortunately, it turns out your immune age can go down ...
mag insects image superjumbo v

Disaster interrupted: Which farming system better preserves insect populations: Organic or conventional?

A three-year run of fragmentary Armageddon-like studies had primed the journalism pumps and settled the media framing about the future ...
dead bee desolate city

Are we facing an ‘Insect Apocalypse’ caused by ‘intensive, industrial’ farming and agricultural chemicals? The media say yes; Science says ‘no’

The media call it the “Insect Apocalypse”. In the past three years, the phrase has become an accepted truth of ...
globalmethanebudget globalcarbonproject cropped x

Infographic: Cows cause climate change? Agriculture scientist says ‘belching bovines’ get too much blame

A recent interview by Caroline Stocks, a UK journalist who writes about food, agriculture and the environment, of air quality ...
organic hillside sweet corn x

Organic v conventional using GMOs: Which is the more sustainable farming?

Many consumers spend more for organic food to avoid genetically modified products in part because they believe that “industrial agriculture” ...
benjamin franklin x

Are most GMO safety studies funded by industry?

The assertion that biotech companies do the research and the government just signs off on it is false ...
gmo corn field x

Do GMO Bt (insect-resistant) crops pose a threat to human health or the environment?

Bt is a bacterium found organically in the soil. It is extremely effective in repelling or killing target insects but ...

Environmental Working Group: EWG challenges safety of GMOs, food pesticide residues

Known by some as the "Environmental Worrying Group," EWG lobbies for tighter GMO legislation and famously puts out annual "dirty dozen" list of fruits and ...
m hansen

Michael Hansen: Architect of Consumers Union ongoing anti-GMO campaign

Michael K. Hansen (born 1956) is thought by critics to be the prime mover behind the ongoing campaign against agricultural biotechnology at Consumer Reports. He is an ...
News on human & agricultural genetics and biotechnology delivered to your inbox.
Optional. Mail on special occasions.
Send this to a friend