A more general targeted sequencing approach focuses on genes or regions well-supported (e.g., by GWAS) for involvement in a trait or disease, but is not generally limited to the coding sequence within the target region. Well-supported regions have been observed in a variety of important traits like type 2 diabetes and Crohn's disease, and to a lesser extent in schizophrenia. In traits for which extensive sequence data have already been generated, excess rare variation has in fact been detected in cases compared to controls, or in individuals at different points on a quantitative trait distribution. This provides support for the idea that there may be very rare genetic variants that affect common phenotypes, like the type social scientists are interested in.
