Most cases of red-green colorblindness are inherited as an X-linked recessive characteristic. Which of the following are possible if a woman, who is a carrier for colorblindness, has offspring with a male who is colorblind?

Question

Quizplus · Accepted Answer

A woman who is a carrier for colorblindness has one normal X chromosome and one X chromosome with the colorblindness allele. A male who is colorblind has one normal Y chromosome and one X chromosome with the colorblindness allele. When they have offspring, the woman can pass on either her normal X chromosome or her X chromosome with the colorblindness allele to her sons. The man can only pass on his Y chromosome to his sons. Therefore, all of their sons will have normal color vision. The woman can pass on either her normal X chromosome or her X chromosome with the colorblindness allele to her daughters. The man can pass on either his normal X chromosome or his Y chromosome to his daughters. Therefore, half of their daughters will be carriers for colorblindness and half of their daughters will have normal color vision.

Most Cases of Red-Green Colorblindness Are Inherited as an X-Linked