Question

Punnett squares are used to show possible combinations of alleles or to predict the probability of a trait occurring in offspring. A parakeet that is heterozygous for blue feathers (dominant) is crossed with a parakeet that is homozygous for white feathers (recessive).

A parakeet with white feathers. A parakeet with blue feathers.

According to the Punnett square for this cross, what percentage of offspring is predicted to have blue feathers?
25 percent
50 percent
75 percent
100 percent

Answer 1

50 percent

Explanation: Let B = blue (dominant) and b = white (recessive). Cross Bb × bb. Punnett square gives Bb and bb offspring in a 1:1 ratio, so half (50%) show the blue phenotype.