The genes that make some people seek higher education seem to have been selecting themselves out of our genome for the last 80 years, a new study has found. The authors think that this process of negative selection will have a big effect on the evolution of the human race in the future centuries.

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Researchers from the Iceland-based genetics firm deCODE have studied the genomes of over 129,808 natives looking for genetic markers that predispose people to achieve longer periods of education. The team looked at the birth rates of these people (all between 1910 and 1990) and sequenced the genome of each individual.

By comparing this genetic data to their level of education, the team found that a genetic factor was involved in a person’s likelihood of attending school for longer. The last step was to create a ‘polygenic score’ based on more than 600,000 sequence markers in the genome to estimate a person’s genetic predisposition for education.

Still, genetics obviously isn’t the only factor that dictates a person’s levels of education. After correlating the polygenic score with environmental, social, and biological factors, however, the researchers found individual with higher scores were less likely to have many children.

Running out of a good thing

In essence, they found that these genes also made people less likely to have a large family — meaning that in the end, smart people contribute less and less to the country’s gene pool.

“As a species, we are defined by the power of our brains. Education is the training and refining of our mental capacities,” said Kari Stefansson, CEO of deCODE.

“Thus, it is fascinating to find that genetic factors linked to more time spent in education are becoming rarer in the gene pool.”

This finding doesn’t mean that people are dumber than ever. Modern education along with a wider access to schools and information than before should balance out or even over-match the genetic effect. However, after a few centuries’ worth of this effect adding up, we could be in some serious trouble.

“In evolutionary time, this is a blink of an eye. However, if this trend persists over many centuries, the impact could be profound.”

Overall, the average polygenic score was on a slow but evolutionary-significant decline. They also found a drop in average IQ of about 0.04 points per decade. But that might be an understatement of the problem — as Ian Sample from The Guardian reports, “that figure might rise to 0.3 points per decade” if the researchers included “all the genes that contribute to education”.

Fighting biology with textbooks

The team believes that smarter people don’t have fewer children because they’re busy doing smart stuff instead of pestering the opposite sex. It seems that the genes involved in education can actually affect their fertility on a biological level. They report that the carriers of these genes tended to have fewer children on average than those who didn’t even if they had the same level of education.

The study was performed using only subjects in Iceland, so there’s no guarantee as of now that people in other countries are going through the same process. Still, it’s something that we’d better keep an eye on. The results go to show the importance of continuing and improving education access and quality all over the world.

“In spite of the negative selection against these sequence variations, education levels have been increasing for decades. Indeed, we control the environment in which these genetic factors play out: the education system,” Stefansson said in a press statement.

“If we continue to improve the availability and quality of educational opportunities, we will presumably continue to improve the educational level of society as a whole.”

“Time will tell whether the decline of the genetic propensity for education will have a notable impact on human society.”

The full paper “Selection against variants in the genome associated with educational attainment” has been published in the journal PNAS.