Question

Cross two heterozygous black mice and tell the possible phenotypes and

genotypes in their offspring.

Answer 1

The correct answer is -

Phenotype: 3:1 (dominant black mice: recessive brown allele)

genotype: 1:2:1 (purebred dominant : heterozygous: purebred recessive)

Step-by-step explanation:

In the given question there is a cross that takes place between two heterozygous black mice. LEt assumes B is black which is the dominant allele and b is the recessive allele or brown. As it is given in heterozygous condition black mice are present which means the B is dominant over b.

Now cross:

Gametes: B and b for each mice

B b

B BB Bb

b Bb bb

By the cross, there are two phenotypic offspring that produce 3 black mice out of four and 1 brown or recessive allele out of four

And, genotypically three offspring in the ratio of 1:2:1 (purebred dominant : heterozygous: purebred recessive)