Joshua is colorblind, but neither of his parents are colorblind. Which of the following is the most likely scenario?

Question

Quizplus · Accepted Answer

Colorblindness is often a sex-linked trait, typically associated with the X chromosome. Since Joshua is colorblind but neither parent is, the most likely scenario is that his mother carries one allele for colorblindness (making her a carrier without expressing the trait) and passed it to Joshua. Males have only one X chromosome (inherited from their mother), so receiving one allele for colorblindness would result in the condition.

Joshua Is Colorblind, but Neither of His Parents Are Colorblind