Question

In peas, yellow color is dominant to green. What will be the colors of the offspring of the following crosses?

a. homozygous yellow x green
b. heterozygous yellow x green
c. heterozygous yellow x homozygous yellow
d. heterozygous yellow x heterozygous yellow

Answer 1

A heterozygous pea has one dominant yellow gene and one recessive green gene. In order for a pea to be green both of its genes has to be green also both of the genes for a green pea are green.
a) You have a 1/2 chance of getting a green gene from one parent and a 1/2 chance of getting a green gene from the other parent therefore you have a 1/2 x 1/2 which equals 1/4 chance of getting a green seed.
b) You have a 1/2 chance of getting a green gene from the first parent and a 100% chance of getting a green pea from the second parent. So 1/2 x 1 equals a 1/2 chance of getting green
c) You have a 100% chance of getting a green pea from both parents thus you have a 100% chance of getting a green seed.

Answer 2

a. 100 % yellow
b. 50% yellow 50% green
c. 100% yellow
d. 75% yellow 25% green