Your grandfather has blue eyes. What is the chance that you have the same gene responsible for this characteristic yourself?

Question

Quizplus · Accepted Answer

The gene for blue eyes is recessive, meaning both parents must carry it for a child to have blue eyes. If your grandfather has blue eyes, he has two recessive alleles. Assuming one of your parents is his child, they would have one recessive allele. The chance you inherit this allele from one parent is 50%, but you need two to express the trait. If the other parent doesn't carry the allele, the chance you have both is 25%.

Your Grandfather Has Blue Eyes