People who are genetically predisposed for high academic achievement tend to marry and have children with partners with similar DNA, according to a new study published in the journal Intelligence.
Most romantic partners are not chosen randomly, but rather through “assortative mating,” meaning that people with similar phenotypes tend to pair up with one another more often than would be expected under a random mating pattern. This might involve pairing up with mates who have similar traits regarding age, skin color, weight, intelligence or education.
While it is well known that humans mate assortatively in relation to education — in that people with similar education levels tend to pair up — this is one of the first studies to show that this phenomenon is highly influenced by DNA.
The researchers say that DNA-led assortative mating could potentially increase genetic and social inequality in future generations, since children of couples who mate assortatively are more unequal genetically than those of people who mate more randomly.
The study was co-led by Dr. David Hugh-Jones from the University of East Anglia’s (UEA) School of Economics and by Dr. Abdel Abdellaoui of the Department of Biological Psychology at Vrije Universiteit (VU) in Amsterdam.
The researchers looked at whether assortative mating for educational achievement could be detected in the DNA of approximately 1,600 married or cohabiting couples in the U.K. The data was drawn from the U.K. Household Longitudinal Study, a representative sample of the population.
The researchers found that individuals with a stronger genetic predisposition for higher educational achievement also had partners who were more educated.
They also tested whether their data could be explained by other factors; for example, by people simply meeting their partners because they lived in the same county. So they re-matched individuals with random partners within the same educational levels and geographical locations.
However, they found that the genetic scores of the original couples showed greater similarities than the randomly generated pairs, indicating significant genetic assortative mating for educational attainment regardless of educational level and geographic location.
“Our findings show strong evidence for the presence of genetic assortative mating for education in the U.K.,” said Hugh-Jones, a senior lecturer in economics.
“The consequences of assortative mating on education and cognitive abilities are relevant for society, and for the genetic make-up and therefore the evolutionary development of subsequent generations.”
He adds that this type of assortative mating could increase social inequality in terms of education or income.
“When growing social inequality is, partly, driven by a growing biological inequality, inequalities in society may be harder to overcome and the effects of assortative mating may accumulate with each generation.”
Source: University of East Anglia