The multiple choice questions have five answer choices — one (and only one) is correct in each case.
In a breeding experiment using gray and white mice of unknown genotypes, the following results were obtained.
If two gray progeny of cross IV mate with each other, what is the probability that any one individual offspring will be gray?
Select an Answer
In cross IV, since the gray female parent must be homozygous dominant and the male parent is homozygous recessive, all of the offspring are heterozygous. The expected results from a cross of two heterozygous individuals is a phenotypic ratio of 3:1, resulting in a 0.75 (or 75%) probability that the offspring will show the dominant phenotype (gray) and a 0.25 (or 25%) probability that the offspring will show the recessive phenotype (white).