In a particular type of cat, coat color follows the dominant/recessive pattern of inheritance. The allele for a brown coat (B) is dominant to the allele for a white coat (b).

Question

One of Mariam's cats is homozygous dominant (BB) and the other cat is heterozygous (Bb). Which of the following is true about Mariam's cats?
A.
They have the same genotype and the same phenotype.
B.
They have different genotypes but the same phenotype.
C.
They have the same genotype but different phenotypes.
D.
They have different genotypes and different phenotypes.

Answer 1

The correct answer is B. They have different genotypes but the same phenotype.

Explanation:

• The homozygous dominant cat has the genotype BB and will express the dominant phenotype, which is brown coat color.
• The heterozygous cat has the genotype Bb and will also express the dominant phenotype (brown coat color) because the brown coat color allele (B) is dominant over the white coat color allele (b).

Since both cats express the same phenotype (brown coat color) but have different genotypes (one is BB and the other is Bb), option B is the accurate description.