In some cats, black coat color (B) is dominant over brown (b) and a striped fur pattern (S) is dominant over a marbled fur pattern (s). You rescued a black striped cat from an animal shelter but could not determine its exact genotype. To do so, you mated the cat with a brown marbled cat. The mating produced 3 brown marbled, 2 brown striped, 2 black marbled, and 3 black striped. Immediately, you concluded the genotype of your rescued cat was
A) BBSS.
B) BBSs.
C) BbSS.
D) BbSs.

Question

Quizplus · Accepted Answer

We can use the information from the offspring to determine that the brown marbled parent must be homozygous recessive (bbss). We know that the rescued cat must have at least one dominant allele for black coat color and at least one dominant allele for striped fur pattern, since it produced black striped offspring. The fact that it produced both black and brown offspring means it must be heterozygous for coat color. We can use a Punnett square to determine that the rescued cat must be heterozygous for both traits: BbSs.

In Some Cats, Black Coat Color (B) Is Dominant Over