Question

A man whose father was colour-blind marries a woman who had a colour- blind mother and a normal father. What percentage of the male children of this couple will be colour-blind?

पर्याय

• 25%

• 0%

• 50%

• 75%

Answer 1

50%

Explanation:

Colour blindness is an X-linked recessive disorder. The son is not color-blind since his father (X^cY), who is color-blind, only gives his X^c chromosome to his daughters. The woman is a carrier (XX^c) because her father is normal (XY) and her mother is color-blind (X^cX^c). The possible offspring in the given case XY (father) × XX^c (mother):

Sons: 50% XY (normal), 50% X^cY (colour-blind) 

Daughters: 50% XX^c (carrier), 50% XX (normal)