Explain polygenic inheritance with the help of an example.
Polygenic inheritance occurs when one character is controlled by two or more genes. Often the genes are large in quantity, but small in effect.
Examples of human polygenic inheritance are height, skin color, eye color and weight. Human skin color is a good example of polygenic (multiple genes) inheritances.
Assume that three ‘dominant’, capital letter genes (A, B and C) control dark pigmentation because more melanin is produced. The ‘recessive’ alleles of these three genes (a, b and c) control light pigmentation because lower amounts of melanin are produced.