AP BIOLOGY

EVOLUTION

HARDY WEINBERG EQUILIBRIUM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If XB = normal vision and Xb = colour blind, what are the chances of a colour blind female having a colour blind son if she has children with a man with normal vision?
A
100%
B
75%
C
50%
D
0%
Explanation: 

Detailed explanation-1: -Since males only have on X chromosome, if it is present, it will be expressed. So if a female is color blind, her genotype would be XbXb, and a man with normal vision would have the genotype XBY. There would be a 100% chance of male offspring being colorblind.

Detailed explanation-2: -Each daughter has a 50% chance of being a carrier and each son has a 50% chance of being color blind. The daughters who are carriers can have color blind sons with the same logic.

Detailed explanation-3: -Hence, probability of an affected daughter is one out of two or 1/2 or 0.50.

Detailed explanation-4: -Final answer: A marriage between a colourblind man and a normal woman produces all carrier daughters and normal sons.

Detailed explanation-5: -Answer and Explanation: There is zero probability that the female offspring between a male with normal vision (XEY X E Y )and a colorblind female (XeXe X e X e ) will be colorblind.

There is 1 question to complete.