Answer:
The correct answer is -
Phenotype: 3:1 (dominant black mice: recessive brown allele)
genotype: 1:2:1 (purebred dominant : heterozygous: purebred recessive)
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)
