Niha Zubair, Arivale Clinical Research Scientist, PhD
Your genetics could play a role in determining whether you’re a high-school dropout or the holder of a four-year college degree. And, that role may even be more important than other factors, such as your family’s income level.
The number of years someone goes to school, also known as “educational attainment,” is associated with a myriad of factors – including one’s ultimate socioeconomic status, health, and longevity. For this reason, both social and health researchers are interested in measuring and accounting for educational attainment.
One recent study of almost 300,000 individuals published in Nature found that educational attainment is partially explained by genetics. Now, a new study published last month in Nature Genetics and covered by The Atlantic has expanded on this work by looking at how genetics associates with educational attainment in over 1 million individuals. Specifically, researchers did a genome-wide association study (GWAS), meaning they essentially looked across the entire genome of these 1 million individuals to find genetic variants associated with educational attainment.
Study participants were of European descent taken from multiple cohorts, including 23andMe. Educational attainment was assessed by questionnaire (e.g. “What is the highest level of education you have completed?”). On a smaller subset of individuals, researchers also examined the influence of genetics on cognitive performance, self-reported math ability, and hardest math class completed.
From the GWAS, researchers identified 1,271 genetic variants (single nucleotide polymorphisms, or SNPs) that significantly – statistically speaking – associated with educational attainment. Each SNP on its own had a small effect on educational attainment. Some of these SNPs are in or near genes involved in brain-development processes and neuron-to-neuron communication.
To examine the combined effect of SNPs on educational attainment, researchers developed polygenic scores and examined their predictive power. In this study, the higher an individual’s polygenic score, the higher their genetic predisposition for increased educational attainment. In other words, the higher your score, the more likely – genetically – you are to have achieved a higher level of education.
These scores explained about 11 percent to 13 percent of the variance in educational attainment. To put this in perspective, the percent variance explained by genetics is lower than what is explained by both parents’ education (about 22 percent) but higher than household income (about 7 percent). These scores also explained about 7 percent to 10 percent variance in cognitive performance.
While there’s debate on how these study results will be interpreted or used – for policy purposes or discrimination, for example – it’s interesting to note that genetics, along with other well-established factors like parents’ education and income, associates with years of education.
For their part, researchers from this study hope their findings will be used in social and health research. For example, if researchers are studying how a new education policy affects high-school drop-out rates, they would typically control for factors such as household income, neighborhood, race, and sex (all potential drop-out influencers that interfere with understanding the underlying question). Now, researchers can also control for genetics and potentially better examine the question at hand.
There are some caveats to the findings from the study, however.
Study participants were from various cohorts, and educational environment may have differed by cohort as educational environments change by location and time. Interestingly, when researchers looked at the effects of SNPs on educational attainment across cohorts, they found evidence of differing effects. This highlights that the results in this study could be dependent on the educational environment studied.
In addition, this score for educational attainment had a much lower predictive power in a sample of African-American individuals than in a sample of individuals with European ancestry. This is because the study was conducted in participants of European descent; hence the genetic variants identified are more tailored to this population. It’s possible this polygenic score would also have reduced predictive power in individuals of other non-European ancestries.
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