Genetic determinism is the idea that genes determine a physical or behavioural phenotype. The term may be applied to the mapping of a single gene to a single phenotype or to the idea that all phenotypes are determined by genes. While the former is well established, the latter is generally rejected by biologists, and is poorly defined.
Evidence for the genetic influence on phenotypes comes from hereditary diseases, for instance, cystic fibrosis and sickle cell anemia, which are caused by mutations in single genes, and Down syndrome and Klinefelter's syndrome by the abnormal duplication of a chromosome. Though the difference between the normal and disease phenotypes are caused by mutations in single genes, the actual development of both involves many interacting genetic and environmental factors.
Definitions of genetic determinism varies. It is often thought of as the hypothesis that all physical and behavioural phenotypes are determined solely by genes. This is sometimes attributed to biologists by the media or some in the social sciences, or attributed to proponents of evolutionary psychology, though in this sense biologists (e.g. Dawkins 2003) would consider it a straw man.
Other less strong definitions include the theory that behavioural traits in animals and humans are to some extent influenced by genetics.
Last updated: 05-13-2005 07:56:04