Compared to environmental factors such as diet, family circumstances and opportunity, this hard-wiring has only a meagre influence, accounting for less than half of 1% of the outcome.
Even when combined with all known genetic variants across the human genome, that share only rises to about 3%. But the findings, published in Nature, are robust enough to help researchers match genetically linked personality traits – such as grit and contentiousness – with education attainment, at least at the level of society, if not the individual. Even a single gene could have an impact.
“For the variant with the largest effect, the difference between people with zero copies and those who have two copies predicts, on average, about nine more weeks of schooling,” said Daniel Benjamin, a professor at University of Southern California.
The most common type of genetic variants – known as SNPs (or “snips”) – can show up as deletions or duplications of DNA fragments.
Earlier research by the same team of 250 scientists worldwide canvassed the genomes of 100000 people, and only turned up three relevant genes. This time the Social Science Genetic Association Consortium tripled the number of genomes sequenced, resulting in a much richer haul.
All 300,000 people were of European descent, partly because most data available comes from the US, Europe and Australia.
There’s still a long way to go, said Peter Visscher, a scientist at the Centre for Neurogenetics and Statistical Genomics at the Queensland Brain Institute in Australia.
“We know from studies on twins and other relatives the total contribution from genetic variants on individual differences on educational attainment is 20% to 40%.”
Ramping up sample sizes to millions, rather than thousands, could fill most of that gap, he said.
“We have only identified the ‘tip of the iceberg’ in our study,” added Philipp Koellinger of Vrije Universiteit Amsterdam. The genes singled out by the study were strongly active in the brain – especially prenatally – and probably play a role in neural development, the researchers found.
Source: Times Live