Two laws of inheritance attributed to Gregor Mendel in recognition of his experimental investigations with peas. Mendel's first law, the Law of Segregation, states that while an organism may contain a pair of contrasting alleles, e.g. Tt, these will segregate (separate) during the formation of gametes, so that only one will be present in a single gamete, i.e. Τ or t (but not both or neither). Mendel's second law, the Law of Independent Assortment, states that the segregation of alleles for one character is completely random with respect to the segregation of alleles for other characters. Thus a TtGg individual will produce equal numbers of all four possible kinds of gametes: TG, Tg, tG, tg. Mendel's first law is still applicable for all chromosomal genes. Mendel's second law is only true if the genes involved are on nonhomologous chromosomes. See also linkage. |
