ABSTRACT
Any behaviour requires movement, and motor structures such as muscles, and glands are built by genes. Thus all behaviour has a strong genetic component. The interesting question is whether behavioural differences between individuals are due predominantly to genetic or to environmental factors, and what is the scale of their respective contributions. There are a number of basic methods used by behavioural geneticists which range from the simple to the almost intractable. Gregor Mendel’s law of segregation illustrates how any character that is determined by a single locus will segregate in a 3:1 ratio in the F2 (second filial) generation, assuming complete dominance of one of the alleles. The behavioural phenotypes that are commonly studied are cognitive abilities such as intelligence quotient, and the psychopathologies such as schizophrenia and unipolar and bipolar depression. However, a range of other personality variables have also been studied, together with such talents as musical ability, and creativity.
