To appear in: Special Issue of Developmental Psychobiology on Converging Methodological Approaches to the Study of Developmental Science Different approaches to relating genotype to phenotype in developmental disorders

In this paper we discuss the complex problem of relating genotype to phenotype and challenge the simple mapping of genes to higher-level cognitive modules. We examine various methods that have been used to investigate this relation, including quantitative genetics, molecular genetics, animal models, and in-depth psychological and computational studies of developmental disorders. Both single gene and multiple gene disorders indicate that the relationship between genotype and phenotype is very indirect and that, rather than identifying mere snapshots of developmental outcomes, the process of ontogenetic development itself must be taken into account.