Existing behavior-genetic research implicates substantial influence of heredity and modest influence of shared environment on reading achievement and reading disability. Applying DeFries-Fulker analysis to a combined sample of twins and adoptees (N = 4886, including 266 reading-disabled probands), the present study replicates prior findings of considerable heritability for both reading achievement and reading disability. A simple biometric model adequately described parent and offspring data (combined N = 9430 parents and offspring) across differing types of families present in the sample Analyses yielded a high heritability estimate (around 0.70) and a negligible shared-environmentality estimate for both reading achievement and reading disability. No evidence of gene. ×. environment interaction was found for parental reading ability and parental educational attainment, the two moderators analyzed.
Bibliographical noteFunding Information:
This work was supported by U.S. Public Health Service grants # AA09367 , MH066140 , DA005147 , DA013240 , and AA011886 .
- Adoption study
- Behavior genetics
- Reading achievement
- Reading disability
- Twin study