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Do you know what a polygenic score is? And how it could affect your teaching? Or even if it should?
It’s a complicated concept but, essentially, a polygenic score is a rating of your genetic likelihood to present with a specific disease, trait or behaviour. The scores, and their use in education, feature heavily in behavioural geneticist Robert Plomin’s book Blueprint: how DNA makes us who we are.
Most of his research is based on the Twins Early Development Study (TEDS), set up in 1994 at King’s College London. Following around 15,000 sets of twins, it is one of the longest-running and largest twin studies in the world.
The study looks at the similarity between identical twins brought up in the same environment and between non-identical twins brought up in the same environment in areas such as cognitive ability, educational outcomes, personality and health. As of 2018, the research had 55 million items of data, and the study is ongoing.
So, what does it reveal? Put simply, everything is heritable to a certain degree. How clever you are, your level of aggression, even how much TV you watch. But where do polygenic scores fit in? Well, Plomin believes we have the power to use DNA as a probabilistic predictive measure.
For example, Plomin’s own polygenic score for schizophrenia is in the 85th percentile. His score means that he is much more likely to be diagnosed with schizophrenia than someone in the 5th percentile of the distribution, as he has more of the DNA differences associated with schizophrenia. It does not mean he will definitely acquire it or that the person in the fifth percentile will not.
Inevitably, polygenic scores have emerged for education, too: the EA3 polygenic score, it’s claimed, can predict individual differences in education better than family income. This score supposedly explains 11-13 per cent of individual differences in how long people stay in education, and 7-10 per cent of individual differences in cognitive ability.
“If all you know about people is their DNA,” Plomin writes in Blueprint, “you can, indeed, predict their school achievement.”
Plomin highlights a study in which polygenic scores predicted 15 per cent of the variance in GCSE scores among 16-year-olds. For comparison, he says, Ofsted inspections predict less than 2 per cent of the variance in children’s GCSE scores.
“It is probably one of the best predictors we have for educational achievement, but you can take kids in the lowest 10 per cent of the distribution for EA3 and some of them will get GCSE scores as good as some of those at the high end. But if you divide it into deciles, and say ‘what is the average GCSE score?’, it is predictive.”
EA3 and what comes after it has the potential to change education. Currently, we rely on socioeconomic measures to intervene in a child’s life to create equal access to opportunity: for example, pupil premium and free school meals. But EA3 may offer a better predictor of not just who needs intervention but what for. Polygenic scores, Plomin argues, could therefore help us to create better interventions.
What we have now is not fit for purpose, he says: “[We need to] expose bullshit like growth mindset - the gimmicks. To think there is some simple cheap little thing that is going to make everybody fine, it is crazy.
“Good interventions are the most expensive and intensive; if it were easy, teachers would have figured it out for themselves. I would like education researchers to use genetics as a variable and see what happens - I predict it will wipe the floor with other measures.”
Jon Severs is the editor of Tes
Commentary: ‘Everything Plomin said still stands’
Kathryn Asbury is a psychologist researching the implications of genetics for education at the University of York. She says:
When Robert Plomin’s controversial book Blueprint was released in 2019, he said: “The book is everything I know. I do not want to write another one.”
The argument he made about education was similarly frank. Speaking to Tes, he claimed that “schools, teachers and parents are not what makes us different from each other” and that our DNA can shed light on how to make education work better for everyone.
Plomin’s view is that education can be improved if we embrace the fact that pupils differ in traits such as attainment, self-regulation and conscientiousness, partly for genetic reasons.
If, for example, we incorporate DNA data into intervention research, it will allow us to assess with unprecedented clarity what works for whom, revolutionising our approach to intervention in schools. He also suggests that DNA could be used as a probabilistic predictor of how well children will thrive in school, meaning interventions could be made earlier to alleviate risks.
This latter point is partly what makes his book controversial because polygenic scores - the DNA predictors Plomin refers to - do not actually predict well at the individual level. They are likely to be valuable to intervention research in general, but they cannot tell us that “Baby X” is likely to be a maths whizz, while “Baby Y” will almost certainly be dyscalculic.
Plomin clearly acknowledged this in both his Tes interview and in Blueprint. However, his “fortune-telling” metaphors have led to a backlash from within the scientific community. This is symptomatic of the fact that the language of risk and probability is often misused and misunderstood.
Given the speed of scientific progress in this area and the ways it could affect us all, I would argue that we need a major public education campaign focused on what polygenic scores can and can’t tell us; on what they can help with and what they can’t.
Yet despite the backlash, Plomin was happy to have got people talking. Since the publication of Blueprint, there have been several books and reports on the potential benefits and risks of genomic research, and the implications for social justice.
A new polygenic score for educational attainment (EA4) is also set to be published very soon and it is likely to be even more powerful than the one Plomin described (EA3), which already carries as much predictive power for attainment as family income does.
Everything Plomin said in 2019 still stands. As we zoom in on the relationship between the genome and life outcomes, our understanding will become ever more nuanced. It is vital that the education sector continues to engage with genetic research if it is to ensure that DNA data is used to benefit pupils, not divide them.
