Evidence for Common Etiological Influences on Early Literacy Skills in Kindergarten.

Understanding how the etiology of print awareness and phonological awareness are related to the etiology of decoding can provide insights into the development of word reading. To address this issue, we examined the degree of overlap among etiological influences of pre-reading skills in 1,252 twin pairs in kindergarten. Genetic, shared environmental, and non-shared environmental factors were significant for all three literacy phenotypes. The majority of genetic and shared environmental influence on decoding was due to common factors that included print awareness and phonological awareness. Notably, only a single genetic factor contributed to all three literacy phenotypes but there was additional shared environmental influence common to phonological awareness and decoding. Findings suggest commonalities in the etiology of pre-reading literacy skills that could inform work on the development of reading skill.