Question

Purple petal color in pea plants is dominant to white petal color. Two heterozygous pea plants are crossed.

What is the ratio of the offspring with white petals to the total number of offspring?
:

Express this in a percentage.
%

Answer 1

Answer: 1/4, or 25%

Explanation: In this example, the "A" allele will code for the dominant, purple color, and the "a" allele will code for the recessive, white color. Plants with purple leaves can be either AA or Aa (A is dominant over a) and plants with white leaves can be aa. Two heterozygotes (Aa) will be crossed:

A a

A AA Aa

a Aa aa

3/4 of the offspring of this cross will have purple leaves (AA and Aa individuals), while 1/4 (25%) will have white leaves.