Question

The iris of the human eye can have many colors, including brown, blue, green, and hazel. How does polygenic inheritance explain why many iris colors are possible?
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Answer 1

Answer:

Some physical characteristics, such as the color of the human skin or eyes, are controlled by at least two genes. These traits are known as polygenic traits. The number of genes that determine the color of the iris is unknown, but the most significant of them are found in Chromosome 15 and they are named OCA2 and HERC2. These genes are associated with the production of melanin.

Explanation: Polygenic inheritance describes the inheritance of traits that are determined by more than one gene. These genes, called polygenes, produce specific traits when they are expressed together. Polygenic inheritance differs from Mendelian inheritance patterns, where traits are determined by a single gene. Polygenic traits have many possible phenotypes (physical characteristics) that are determined by interactions among several alleles. Examples of polygenic inheritance in humans include traits such as skin color, eye color, hair color, body shape, height, and weight.