Question

In guinea pigs, B = black, b = brown, S = short hair, s = long hair. A heterozygous black, short-haired animal reproduces with a brown, long-haired animal. What is the expected phenotypic ratio of the offspring?

Answer 1

Answer:

1/4 black short hair

1/4 black long hair

1/4 brown short hair

1/4 brown long hair

Explanation:

Heterozygous black Bb, short hair SS

Brown bb, long hair ss

Hence, heterozygous black, short-haired = BbSs

Brown, long-haired = bbss

BbSS   x   bbss

progeny genotype = 4BbSs, 4Bbss, 4bbSs and 4bbss (see the attached image)

Phenotype = 4 black, short-haired, 4 black long-haired, 4 brown short-haired and 4 brown, long hair

Hence, the expected phenotype ratio of the offspring is;

• 1/4 black short hair
• 1/4 black long hair
• 1/4 brown short hair
• 1/4 brown long hair