ABSTRACT
On a global scale and within diverse nations such as the United States, there are large educational and cultural differences related to literacy development. However, significant individual differences in literacy are still present within relatively homogeneous environments for reading development. This chapter explores the balance of genetic and environmental influences on individual differences in reading and on reading disability (extreme poor reading) in generally supportive educational environments. Evidence from identical and fraternal twins’ behavior showing strong genetic influences on reading disability is supported with molecular genetic evidence from their DNA. Linkage analyses indicate regions on several different chromosomes where genes related to reading disability are likely to be found. Implications are discussed for current educational policy, possible future diagnosis of risk, and gene therapy for reading disability.
