In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s).If two dihybrids (Bb Ss) are crossed, the most common phenotype will be
A)black and solid.
B)black and spotted.
C)red and solid.
D)red and spotted.
E)none of these.

Question

Quizplus · Accepted Answer

When two dihybrids (Bb Ss) are crossed, the possible gametes are:
BS, Bs, bS, bs
The Punnett square for this cross can be done as shown below:

|   | B  | b  |
|---|---|---|
| S | BS | bS |
| s | Bs | bs |

From this Punnett square, we can see that the most common phenotype is black and solid, which corresponds to the genotype BBSS, BBsS, BBSs or BBss. These four genotypes out of a total of sixteen possible genotypes will result in the phenotype of black and solid. Therefore, the answer is A.

In Cocker Spaniels, Black Coat Color (B) Is Dominant Over