An understanding of the interplay between genetics and environment on reading acquisition can help inform educational practices and interventions. Estrera et al. (2023) have reviewed the key findings in this area and their article is summarised below. Underpinning this discussion is the understanding that all students (irrespective of their genetic predisposition) benefit from explicit and systematic reading instruction within a positive learning environment to reach their potential.
Reasons for variations in reading skills
- Reading focused twin and family studies show that on average genetics account for 59% of the variation, shared environment accounts for 15% and non-shared environment accounts for 29%.
- There is evidence that the gene for one reading skill (e.g., decoding) overlaps with the genes for other reading skills (e.g., comprehension). This is referred to as the ‘generalist genes hypothesis’.
- Reading disability is influenced by genetics and environmental factors.
- Difficulties in reading tend to be highly correlated with difficulties in other areas (e.g., language development, attentional disorders, maths difficulties).
Findings from developmental studies
- Students are different from each other in their reading skills at any given time.
- Students progress from beginning readers to text comprehenders at different rates.
- Longitudinal research indicates the environment has a stronger impact on reading development overtime for any given student. It is hypothesised that direct instruction in reading accounts for this effect.
The interconnection of genes and the environment
- Genes express themselves through the environment, therefore it is necessary to consider the interplay between these two factors.
- Gene-environmental correlations describe how exposure to particular environments are partially determined by genetics. Passive correlations occur when the genes passed on by parents also influences the environment they create (e.g., parents with strong reading skills are more likely to have home libraries and read). Evocative correlations refer to the reactions of others to an individual’s particular genetic trait (e.g., a student who is genetically inclined to be a fluent reader is more often asked to read and thereby has more practice reading). Active correlations occur when an individual seeks out an environment consistent with their own genetic traits (e.g., a student who genetically finds reading difficult will engage in reading avoidance behaviours).
- Gene-environment interactions relates to how a person’s environment strengthens or weakens the effects of their genes on a trait (e.g., students who attend high quality schools had higher genetic influences on their reading skills than those who attended lower quality schools).
Estrera, S., Lancaster, H., & Hart, S. (2023). Genetics and the science of reading. The Reading League Journal, 4 (2), 4-16