Generalist genes: implications for the cognitive sciences.

In the 'generalist genes' hypothesis, it is suggested that the same genes affect most cognitive abilities and disabilities. This recently proposed hypothesis is based on considerable multivariate genetic research showing that there is substantial genetic overlap between such broad areas of cognition as language, reading, mathematics and general cognitive ability. We assume that the hypothesis is correct and consider here its implications for cognitive neuroscience. In our opinion, the two key genetic concepts of pleiotropy (in which one gene affects many traits) and polygenicity (in which many genes affect a trait) that underlie the generalist genes hypothesis imply a 'generalist brain'. That is, the genetic input into brain structure and function is general not specific.