rules of inheritance based on the breeding experiments of the Austrian monk Gregor Mendel (1822–84), which showed that the inheritance of characteristics is controlled by particles now known as *genes. In modern terms they are as follows. (1) Each body (somatic) cell of an individual carries two factors (genes) for every characteristic and each gamete carries only one. It is now known that the genes are arranged on chromosomes, which are present in pairs in somatic cells and separate during gamete formation by the process of *meiosis. (2) Each pair of factors segregates independently of all other pairs at meiosis, so that the gametes show all possible combinations of factors. This law applies only to genes on different chromosomes; those on the same chromosome are affected by *linkage. See also dominant; recessive.
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