A geneticist studies a series of characteristics in monozygo

A geneticist studies a series of characteristics in monozygotic and dizygotic twins, obtaining the concordances listed below. For each characteristic, indicate whether the rates of concordance suggest genetic influences, environmental influences, or both. Explain your reasoning.

Solution

Eye color is mainly influenced by genetic component in mono and dizygotic twins. Handedness in both mono and dizygotic twins is influenced by genetic component. Club foot in monozygotic twins is influenced by both genetic and environmental components and in dizygotic twins is influenced by environmental component. Lung cancer in both monozygotic and dizygotic twins is influenced by only environmental component. In monozygotic twins most of the traits are influenced by genetic components. In dizygotic twins most of the traits are influenced by environmental conditions.