Question

Color blindness is a recessive X-linked trait in humans. In a family where the mother is heterozygous for color blindness and the father is color-blind, the probability of their having a color-blind daughter is:
A.0.
B.1.
C.1/4.
D.1/2.
E.1/16.

Answer 1

Answer:

1/2

Explanation:

Genotype of the heterozygous mother= X^cX

Genotype of color-blind father= X^cY

A cross between heterozygous mother and color blind father would give progeny in following phenotype ratio=

1 colorblind daughter: 1 colorblind son: 1 carrier but normal daughter: 1 normal son.

Therefore, this couple has 1/2 probability of getting a colorblind daughter is 1/2