Genetics Briefly describe the molecular mechanism of the yel

Genetics

Briefly describe the molecular mechanism of the yellow allele in mice. If two mice are mated what would the phenotypic ratio, and corresponding phenotypes of all progeny be.

Solution

Coat colour in mice is decided by a gene called ‘agouti’. It results in brown-black pigmentation of hair. However, some mice turn yellow. While the reason for this is not a separate yellow allele but differential regulation of the agouti gene. There is IAP (Intracisternal A Particle) segment upstream of agouti gene, which is transcribed in the opposite direction to that of the agouti gene. However, a promoter at the 3’ long terminal repeat works in the direction of the agouti gene and makes it constitutively active, which leads to yellow pigmentation.

For the genetic cross discussed, it depends on the phenotype/genotype of the parent.