Color Blindness Transmission

Transmission of Color Blindness Trait

Why are More Males Afflicted Than Females?

Color blindness is a sex-linked trait, specifically X-linked recessive. Males have only one X chromosome (XY), so if they inherit an X chromosome with the color blindness allele, they will express the trait. Females have two X chromosomes (XX), so they must inherit the color blindness allele on both X chromosomes to express the trait. This makes color blindness much more common in males than in females.

What Would Have to Occur Before a Female Would Manifest the Traits of a Color Deficiency?

For a female to manifest a color deficiency, she would need to inherit the recessive allele for color blindness on both of her X chromosomes. This means that her father must be colorblind (as he contributes one X chromosome to his daughters), and her mother must either be colorblind or a carrier of the color blindness allele.