Question

A true-breeding black rabbit is crossed with a true-breeding white rabbit to produce an F1 generation of 16 individuals. If the black color trait is dominant, which of the outcomes represents the expected phenotype of an F1 generation cross?
a. 9 black rabbits, 3 white rabbits, 3 gray rabbits, and 1 spotted rabbit.
b. 0 black rabbits, 16 white rabbits, 0 gray rabbits.
c. 16 black rabbits, 0 white rabbits, 0 gray rabbits.
d. 0 black rabbits, 0 white rabbits, 16 gray rabbits.
e. 5 black rabbits, 4 white rabbits, 7 gray rabbits.

Answer 1

Answer:

c. 16 black rabbits, 0 white rabbits, 0 gray rabbits.

Explanation:

Let dominant black allele be = B

Let recessive white allele be = b

True breeding rabbit would mean that they are homozygous in their genotype hence true breeding black rabbit will be BB and true breeding white rabbit will be bb.

BB X bb :

    B     B

b Bb  Bb

b  Bb  Bb

All the offspring are heterozygous with one dominant B allele so the phenotype black colour will be produced and all 16 individuals of F1 generation will be black in colour.