Behavior Genes

Abstract

Behavior genetics is the study of the inheritance of normal psychological traits, such as personality and cognitive ability, as well as abnormal traits and illnesses, such as mood disorders and psychoses. The questions addressed by behavior genetics include the following: Why do individuals differ? Why aren't children of the same parents alike? To what extent are genes and environmental factors accountable for the differences and similarities in human behavioral traits? What are the salient genes and environmental factors? How do these genes and environmental factors act, coact, and interact to produce the phenotype? To what extent is the covariation of phenotypes the result of the same genes and environmental factors acting on both? Does the extent to which genes affect a phenotype change over the life span and are different genes important at different stages of development? Behavioral traits and disorders, with some rare exceptions, show complex patterns of inheritance involving gene–environment interplay and therefore quantitative genetic methods assume a particularly important role alongside molecular techniques.