Question

In the parental generation, inbred black and an albino mice parents mate. The resulting F1 mice are black and heterozygous at 2 different loci. The F2 population consists of black, white, and albino mice. Albino is epistatic to pigmented. What is the phenotypic segregation ratio of this mouse species in the F2 generation? Enter your answer in the format: "4:3:2". Note lack of color pigmentation is recessive.

Answer 1

The F2 generation from a cross of two heterozygous black mice (AaCc x AaCc), in which albinism is epistatic to pigmentation, results in a phenotypic ratio of 9 agouti:3 black:4 albino.

Step-by-step explanation:

The question you've asked is about the phenotypic segregation ratio in mice when considering epistasis, particularly related to coat pigmentation. Epistasis occurs when one gene's effect masks the effect of another gene. In the case of mice pigmentation, the allele for agouti coloring (A) at one locus is dominant to solid coloring (a), but another gene locus (C) is necessary for any pigmentation to show. A mouse with the homozygous recessive genotype (cc) at the C locus will be albino, exhibiting white fur, regardless of what alleles are present at the A locus. This makes the C gene epistatic to the A gene. When crossing two heterozygous mice (AaCc x AaCc), the F2 generation shows a phenotypic ratio of 9 agouti:3 black:4 albino.

The phenotypic segregation ratio of the mouse species in the F2 generation is 9 black: 3 white: 4 albino.

Answer 2

12:4:3

Step-by-step explanation:

Let the lack of color pigmentation which is recessive be aa where AA and Aa allow for color (BB, Bb - black, baby - white).

The F1 parents are BbAa x BbAa

This cross will produce 12/16 blacks, 4/16 albinos and 3/16 white.