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 know that black coat color (B) is dominant over brown (b) and striped fur pattern (S) is dominant over marbled fur pattern (s). 
From the mating, we see that there are both brown and black offspring, indicating that our rescued cat must have at least one dominant B allele (since all brown offspring must have two recessive b alleles). 
We also see both striped and marbled offspring, indicating that our cat must have at least one dominant S allele (since all marbled offspring must have two recessive s alleles). 
Since we don't know if the rescued cat is homozygous or heterozygous, we can represent the possible genotypes as BbSs. This would result in the 3:2:2:3 ratio of offspring that we observed. Therefore, the correct answer is D) BbSs.

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