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College graduation may be partly determined by your genes, genome study of siblings finds

But researchers find that nurture is stronger and can override nature

Photo of Jill Barshay

Proof Points

Social scientists are curious to see if the human genome project might help answer an age-old question about education: is intelligence, or academic performance, written in our genes?

Two years ago, researchers took a first crack at this. Through data mining the genomes for 100,000 individuals, they were able to isolate clusters of genetic patterns that seemed to be associated with higher levels of education. They didn’t identify education or intelligence genes, specifically, but they found that people who had completed more years of schooling were more likely to share certain genetic variations with each other than with those who had dropped out of school earlier.

But these same genetic patterns were also more commonly found in people who lived in wealthier neighborhoods and were raised by well-educated mothers. Maybe it was good schools and good parenting driving the educational attainment, and not genes at all?

Ben Domingue of Stanford University and a team of researchers figured out a clever way to clear away these confounding factors: study pairs of siblings. Because so much is similar for siblings  (same mothers, same neighborhoods), small differences in their genetic makeup could stand out. And, in an August 2015 paper published in AERA Open, a peer-reviewed journal published by the American Educational Research Association, the researchers found that within families, an adolescent with a higher “polygenic score” than her or his sibling tended to go on to complete slightly more schooling. (A polygenic score is a measure of how many of the genetic variations associated with educational attainment a person has in his or her genome.)

“We do have evidence to suggest that genes are causing differences in educational attainment, but it’s a very small,” Domingue said, explaining that the sibling with a significantly higher polygenic score continued in school for only one-third of a year longer, on average, than the sibling who had a lower score.

Socio-economic factors remain much stronger. For example, having a mother who graduated from college was associated with an additional 1.7 years of schooling.

Interestingly, the researchers found that family environments may magnify small genetic differences between siblings. Perhaps siblings differentiate themselves from one another, forming identities that drive them toward more or less academic-related activities? Or one strives more than another to impress a parent? The study found no relationship between a sibling’s birth order and his or her polygenic score.

Domingue says his results show that the predictive power of genetic information is too weak to be used by educators for any purpose. Unlike genetic mutations for cancer, where you would want to monitor patients so as to detect a disease early, knowing your polygenic score for educational attainment wouldn’t help you with anything.

But Domingue is interested in exploring how the genetic variations for educational attainment may develop into personality traits that lead children to become good students. He wonders if students with high polygenic scores are more sociable, for example. Ultimately, Dominque wants to explore the interaction between genes and the environment, and learn if there are things that schools or teachers can do to moderate genetic antipathies to education.

It’s also important for lay people to be aware that this research into the biology of education is going on. It probably won’t be many years before a researcher identifies the genetic mutations for attention deficit hyperactivity disorder (ADHD), for example, and parents will start demanding early intervention services for their children before any clinical condition can be diagnosed.

Customarily, in academic articles, researchers break their data down by race to show how blacks, whites and Latinos and Asians differ. But in this paper, a table of polygenic scores by race is notably absent.

“That was a deliberate choice,” said Domingue. “We think to include that kind of information would be misleading.”

Domingue went into a long digression, in which he argued that he doesn’t think you can compare genetic patterns across races for technical reasons. To dispute him, you’d need a degree in biology  — not my forte.

“The most contentious area has to do with race,” said Domingue, well aware that this new line of genomic research dredges up a checkered history of racist theories about whether intelligence differs among the races and is genetically determined. (See eugenics and The Bell Curve).

“I have zero interest in trying to explain between race differences in education achievement,” he added. “I don’t think there’s anything there.”

This article also appeared here.

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Jill Barshay

Jill Barshay is a staff writer and editor who writes the weekly “Proof Points” column about education research and data. She taught algebra to ninth… See Archive

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