Study of heredity in general and of gene s in particular.
Modern genetics began with the work of Walter S. Sutton proposed that chromosome s were the site of Mendel's hereditary factors. The Hardy-Weinberg law established the mathematical basis for studying heredity in populations. Thomas Hunt Morgan provided evidence that genes occur on chromosome s and that adjacent genes on the same chromosome form linkage group s. Oswald Avery showed that DNA is the chromosome component that carries genetic information. DNA's molecular structure was deduced by James D. Watson and Francis Crick . These and other developments led to the deciphering of the {{link=genetic code">genetic code of the DNA molecule, which in turn made possible the recombination techniques of genetic engineering . An understanding of genetics is necessary for the diagnosis, prevention, and treatment of hereditary diseases, the breeding of plants and animals, and the development of industrial processes that use microorganisms. See also behaviour genetics .