Genetics is the study of how living things receive common traits from previous generations.

These traits are described by the genetic information carried by a molecule called DNA. The instructions for constructing and operating an organism are contained in the organism's DNA. Every living thing on earth has DNA in its cells. A gene is a hereditary unit consisting of DNA that occupies a spot on a chromosome and determines a characteristic in an organism. Genes are passed on from parent to child and are believed by many to be an important part of what decides looks and behavior. Darwin’s theory of natural selection laid the groundwork for evolutionary theory. However, it was the emergence of the field of genetics, pioneered by Gregor Mendel (1822-1884), that provided the missing information on how evolution works in practice. Mendel’s experiments with peas led him to realise that heredity in sexual reproduction works by the mixing of separate factors, not by the blending of inherited characters. This combination of Darwin's theory and our current understanding of heredity led to the birth of the scientific area called "population genetics.".