Recessive Gene in Mice: Understanding Genetics and Pigment Production

What is the recessive gene in mice that results in white fur?

A. Dark eyes

B. White fur

C. Black fur

D. Red eyes

Answer:

The recessive gene in mice resulting in white fur is the allele at the C locus responsible for the production of pigment.

When considering which of the following is a recessive gene in mice, we must understand the concepts of dominant and recessive genes, as well as epistasis. In mice, the specific gene responsible for pigment production is at the C locus. The allele for pigment production is dominant (C), while the allele for no pigment production is recessive (c). When a mouse has two copies of the recessive allele (cc), it is unable to produce any pigment, making the mouse an albino.

This is true regardless of the alleles present at the A locus, which controls the type of coat coloration such as mottled agouti (A) or solid color (a).

Based on the provided information, white fur in mice is associated with the absence of pigment due to the recessive allele at the C locus. Hence, a mouse must have a genotype of cc to have white fur, regardless of its genotype at the A locus.

Given that the recessive c allele leads to the phenotype of white fur (albinism) when homozygous, the correct answer to 'Which of the following is a recessive gene in mice?' is B. White fur.

Understanding the genetics behind pigment production in mice can provide insights into hereditary traits and the impact of recessive genes on physical characteristics.