When two genes segregate independently, it is called independent assortment. Gregor Mendel, a European monk who studied heredity, identified this process in 1865 while he was investigating multiple generations of pea plants.
Independent assortment occurs during the formation of sex cells, or gametes. In organisms with cell nuclei, called eukaryotes, gametes are made during a specific type of cell division called meiosis. Part of this process involves recombination. Sections of DNA break away and reform in new arrangements that lead to different combinations of genes. When the new sex cells are produced during meiosis, they contain different combinations of chromosomes than were found in the original gamete. During reproduction, independent assortment helps each new organism become a unique individual.