A polygenic trait is the one that is governed by more than one gene. ... These genes control skin pigmentation only, no other phenotypic trait is affected by these genes. Likewise, human eye colour and hair pigment in the mouse are polygenic but tongue rolling in humans is not polygenic

Polygenic Inheritance:

Skin colour in mice is an example of polygenic inheritance. Polygenic inheritance refers to the inheritance of a trait that is controlled by two or more genes, each with multiple alleles. In the case of skin colour in mice, multiple genes contribute to the expression of this trait.

Explanation:

- Skin colour in mice is not determined by a single gene, but rather by the combined effects of multiple genes. Each gene may have different alleles that can influence the overall skin colour phenotype.
- These genes interact with each other and with environmental factors to produce a wide range of skin colours in mice.
- The continuous variation in skin colour seen in mice is a result of the additive effects of multiple genes working together.

Example:

- For example, if one gene controls the production of melanin (the pigment responsible for skin colour) and another gene controls the distribution of melanin in the skin, the combined effects of these genes will determine the final skin colour of the mouse.
- Different combinations of alleles from these genes can result in a spectrum of skin colours, ranging from light to dark.

In conclusion, skin colour in mice is an example of polygenic inheritance, where multiple genes contribute to the expression of the trait. This results in a wide range of skin colours in the mouse population.