Thursday, August 18

Kathryn Paige Harden: ‘Studies have found genetic variants that correlate with going further in school’ | Genetics

KAthryn Paige Harden argues that how far we go in formal education, and the huge knock-on effects it has on our income, employment, and health, is due in part to our genes. Harden is a professor of psychology at the University of Texas at Austin, where she runs a laboratory that uses genetic methods to study the roots of social inequality. His provocative new book it is The genetic lottery: why DNA is important for social equality.

Even talking about whether there might be a genetic element to educational achievement and social inequality breaks a huge social taboo, particularly on the political left, which is where he says his own sympathies reside. The specter of eugenics looms over everything, and no one wants to create a honeypot for racists and classists. To be clear, it is scientifically unfounded to make claims about differences between racial groups, including intelligence, and it is not. But why go here?
I wrote this book first for my fellow scientists, who have not necessarily seen the relevance of genetics to their own work or have been afraid to incorporate it because of these associations. There is a large body of scientific knowledge that is ignored so that the genius of eugenics is not allowed to escape.

But also people hear every day about new genetic discoveries and see in their own families and lives that genetics are important. When asked To estimate how much genes influence intelligence, people’s responses are not zero. I am trying to help you understand that information in a socially responsible way. If you are concerned about social equality, what do you do with the information on genetics?

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He has been accused of promoting eugenics, including by a prominent sociologist. Benjamin dress, who has written in which you are participating “Clever slippage between genetic and environmental factors that would make the founders of eugenics proud”.
Those fears come from a very real place: historically, genetics have been misused. But [eugenics] it is literally the opposite of what I am advocating. The central idea of ​​eugenics is that there is a hierarchy of inferior or superior people that has its roots in biology and that inequalities are justified on that basis. Mine is an anti-eugenics approach that seeks to use our knowledge of genetic science to build social policies and interventions that create more social equality. Sweeping genetic differences between people under the rug does not make the genome, as the systemic force that causes inequality, disappear. That genetic and environmental factors are intertwined at all levels is simply a description of reality.

How do you predict a person’s educational achievement through their genome?
It begins with a statistical correlation exercise called a genome-wide association study (GWAS). That It takes hundreds of thousands of people with similar genetic ancestry and measures tiny genetic differences, of which there are millions, scattered throughout their DNA sequences. He then looks to see which of those variants correlates with his number of years of schooling.

We then take the results and, for a new person’s genetic sequence, we add that information together to produce a single number, a polygenic score, that predicts how far they will go in school.

Crude as it is, the GWAS approach has found genetic variants that correlate with going the extra mile in school. That’s not surprising: we see evidence that there is a genetic influence on academic performance in twin studies. Identical twins are more similar in how far they go in school than fraternal twins.

How many variants are we talking about and what is the size of the effect?
Scientists have identified more than 1,000 genetic variants spread throughout the genome, each of which has a minimal effect. Taking the combined influence, it captures about 10-15% of the variance in educational achievement. The college graduation rate is almost four times higher for people who have a high polygenic score compared to a low one. This competes with other variables that we consider important for educational achievement, such as family income, which has an effect size of around 11%. But it’s still lower than the twin study estimate that approximately 40% of the variation in educational attainment is due to genes.

Can we say that differences in educational attainment are caused by our DNA? Correlation does not equal causation and we know that the environment makes a big difference.
At this point, we are reasonably sure that the causal genetic influence is not zero. It is size that is at stake. There are doubts with the twin studies as to whether they are attributing to genes what should really be claimed by the environment. And for polygenic scoring studies, people can differ genetically in ways that match environmental factors, and it’s really those that are driving the effect.

More confidence in our conclusions arises when we obtain similar answers with different methods. Polygenic scoring studies within families now also suggest a genetic cause. For example, studies of siblings who were raised in the same environment, but who are more different in their polygenic scores, show that these siblings have more different life outcomes.

Are the people who have these genes smarter?
The word “intelligence” is a lightning rod, because it is very easy to misrepresent it as an indicator of all human ability. But it is clear that formal education in the US and the UK reinforces a very particular kind of reasoning. And it’s the same kind of reasoning that IQ tests also pick up.

But we have also done a genetic study who discovered that there is a basket of non-cognitive skills related to personality that help people to advance in school, for example, being conscientious and open to new experiences. Anything that makes you more likely to move on to the next stage of your education, to the extent that it reflects on your biology, a GWAS will pick it up. Importantly, people with these genes do not have “good” genes. They have genetic variants that are correlated with going further in school, as currently constructed.

Will we rush to read our children’s genomes to discover their polygenic scores in the future?
People’s imaginations jump into this world of individualized tests and tailored interventions. I don’t think this knowledge is best used as a diagnostic tool on an individual person. There is always the danger that people will receive incorrect or incomplete information. I want to use genetics as a way to better see what is happening within our environments and social structures.

So how should this knowledge be applied?
One of the most useful applications is improving the basic research we do to design our broader policies and interventions for all. There are many policy initiatives and more are being proposed all the time. But its research base is limited because it assumes that children only receive environments from their parents and not anything genetic.

Consider, for example, policies to close the famous “word gap,” which is the estimated difference of 30 million words between what poor children and children from high-income families hear before their third birthday. The jury is still out on whether “word gap” interventions will be effective, but an obvious problem is that the same vocabulary results that are supposed to be the results of being exposed to more speech could also be the result of genetics. Parents and children share genes and the same genes that are associated with adult education and income. they are also associated with the early acquisition of speech and reading in their children. Before spending millions on interventions designed to change parental behavior in hopes of improving children’s outcomes, it would be wise to at least check for this effect.

Ruha Benjamin also suggested the search for more data to explain things ends up being a barrier to act on what we already know we have to do to solve the academic achievement gap …
I don’t agree that we already know what to do. If you see meta-analysis of educational interventionsYou will see that most of your effect sizes are zero. Most of the things we try in education, even when well-intentioned and well-funded, make no difference in the lives of students. It is a fiction that we have this army of effective and scalable solutions waiting behind the scenes. Finding out what works for whom and when is very difficult. The risk of no To speak of genetics is to continue with the status quo, where we intervene much less than we could be.

The genetic lottery: why DNA is important for social equality It will be published by Princeton University Press on September 21 (£ 25). To support the guardian and observer, request your copy at Shipping charges may apply

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