AP BIOLOGY

HEREDITY

INCOMPLETE DOMINANCE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If a colorblind male marries a woman who is a carrier, what percentage of their FEMALE children will be colorblind?
A
0%
B
25%
C
50%
D
100%
Explanation: 

Detailed explanation-1: -So, the correct answer is ‘50%’.

Detailed explanation-2: -The colorblind father will transfer its carrier X chromosome to the daughter. The women will be a carrier for colorblindness XXc. The colorblind man will be XcY. The carrier female and color blind man will inherit the disease to 50% sons and 50% daughters.

Detailed explanation-3: -Since the female is a carrier, her genotype will be XhX. The male will be XY. Therefore there will be a 50% chance of the sons being colour blind and 50% chance of the sons being normal.

Detailed explanation-4: -A man needs only one copy of a defective gene to be colour blind. A woman needs two copies of defective genes to be colour blind. So when a colour blind man marries a normal sight woman all of their sons will be normal but their daughters will be carriers.

Detailed explanation-5: -Each daughter has a 50% chance for being color blind and a 50% chance for being a carrier.

There is 1 question to complete.