The educational achievement of British teenagers is highly heritable across a range of academic subjects, according to researchers at King's College London.
In their study of over 12,500 twins, genetic factors accounted for 54 to 65 percent of differences in General Certificate of Secondary Education (GCSE) exam performance. Many of the same genes influenced results across subjects, from English, maths and science to art and languages. This shared genetic influence was found even after controlling for the effects of general intelligence.
'We found that over half of the differences between children's educational achievement was explained by inherited differences in their DNA, rather than school, family and other environmental influences,' said Kaili Rimfeld, a research student at King's College London's Institute of Psychiatry, Psychology and Neuroscience, who was first author of the study.
Researchers compared GCSE performances between monozygotic twins, who are genetically identical, and dizygotic twins, who share around half of their genetic material. As all twin pairs grew up in the same families and attended the same schools, shared environmental influences were assumed to be constant.
Twins' intelligence, measured using standard tests of verbal and non-verbal ability, explained just under half of the genetic component of exam results. In the paper, published in the journal Scientific Reports, researchers suggest that other heritable traits such as motivation and personality may help to explain the genetic differences in academic performance.
The study has no immediate implications for education although the authors suggest that, in the future, these results might help with the development of personalised learning programmes. This has, however, been disputed by experts not involved in the study.
Professor Darren Griffin, a geneticist at the University of Kent, said: 'What we need to be careful of ... is leaping to the assumption that this means that people are predisposed to do more or less well in their school exams. Genetics is the science of inheritance, not pre-determinism, and there is no substitute for hard work and application.'
Professor John Hardy of the Department of Neuroscience at UCL commented: 'Twin studies are a mainstay of behavioural genetics, but they make a simple assumption that is unlikely to be true: that is that we treat identical twins the same as we treat non-identical twins (who look much more different from each other). These results are interesting, therefore, but by no means definitive and it would be unwise to make educational decisions based on these data.'