Biology Genetics Question

Question

In rats, black fur (B) is dominant to white fur (b). If you cross 2 heterzygous individuals (Bb) what would be the ratio of different phenotypes in the resulting offspring?

a. all black

b. 1 black: 2 grey: 1 white

c. 3 black: 1 white

d.all white

Answer 1

B b

B BB (black) Bb (black)

b Bb (black) bb (white)

3 Black and 1 White

Answer 2

A heterozygote crossed with a heterozygote will produce a 3 dominant : 1 recessive ratio for phenotypes and a 1 homozygous dominant : 2 heterozygotes : 1 homozygous recessive ratio for genotypes.