Complex cognitive traits such as reading and mathematics are highly heritable and are shown to be associated with quality of life including wealth and life expectancy. That said, there is little understanding of the genetic architecture of cognitive abilities, genetic components and the correlation between them.
Nature Communications published the study as part of the Wellcome Trust Case-Control Consortium 2 in collaboration with the Twins Early Development Study (TEDS). Genome-wide association studies of reading and mathematics ability were performed using data from 2,794 unrelated 12-year-old British children who are identical and non-identical twins.
First author Dr. Oliver Davis, of University College London Genetics, says:
“We looked at this question in two ways, by comparing the similarity of thousands of twins, and by measuring millions of tiny differences in their DNA. Both analyses show that similar collections of subtle DNA differences are important for reading and math. However, it’s also clear just how important our life experience is in making us better at one or the other. It’s this complex interplay of nature and nurture as we grow up that shapes who we are.”
The twins participated in Web and telephone-based reading comprehension and fluency testing together with questions from three components of mathematics, based on the UK national curriculum.
Researchers find substantial overlap in genetic components
Results from the tests were combined with DNA data and showed a substantial overlap in the genetic components that impact reading and mathematics capabilities.
About 50% of genes that have an influence on a child’s reading ability, also have an affect on their mathematics aptitude.
Prof. Robert Plomin, senior author of the research and leader of the TEDS study, reveals that the study does not highlight specific genes responsible for literacy or numeracy, “but rather suggests that genetic influence on complex traits, like learning abilities, and common disorders, like learning disabilities, is caused by many genes of very small effect size.”
Plomin adds: “The study also confirms findings from previous twin studies that genetic differences among children account for most of the differences between children in how easily they learn to read and to do math. Children differ genetically in how easy or difficult they find learning, and we need to recognize, and respect, these individual differences. Finding such strong genetic influence does not mean that there is nothing we can do if a child finds learning difficult – heritability does not imply that anything is set in stone – it just means it may take more effort from parents, schools and teachers to bring the child up to speed.”
Understanding the etiology (causes or origins) of complex cognitive characteristics like numeracy and literacy ability is key to assisting children with achieving their potential and gaining knowledge of population variation in cognitive abilities and the substantial genetic components shared with learning difficulties such as dyslexia and dyscalculia.
According to the Dyslexia Research Institute, currently 10-15% of the US population has dyslexia with only 5% recognized and receiving assistance. Many of these individuals are part of the 44 million adults with the lowest levels of literacy, which limits their ability to find jobs and function independently within their communities.
Lead author Dr Chris Spencer concludes:
“We’re moving into a world where analyzing millions of DNA changes, in thousands of individuals, is a routine tool in helping scientists to understand aspects of human biology. This study used the technique to help investigate the overlap in the genetic component of reading and math ability in children. Interestingly, the same method can be applied to pretty much any human trait, for example, to identify new links between diseases and disorders, or the way in which people respond to treatments.”
Medical News Today recently reported that “Nature beats nurture in exam grade differences.” In this UK study, researchers found that differences in exam grades owed more to genes than the family environment. In math, English and science, genes accounted for nearly 60% of the differences.