Question

question 4 of 11
a colorblind father and a mother who is a carrier for colorblindness have a son. according to mendels laws, what is the probability that the son will be colorblind?
0%
25%
50%
100%

Explanation:

Step1: Understand sex - linked inheritance

Color - blindness is an X - linked recessive trait. Let \(X^b\) represent the color - blind allele and \(X^B\) represent the normal allele. The father is color - blind, so his genotype is \(X^bY\). The mother is a carrier, so her genotype is \(X^BX^b\).

Step2: Determine the possible gametes

The father can produce two types of gametes: \(X^b\) and \(Y\). The mother can produce two types of gametes: \(X^B\) and \(X^b\).

Step3: Analyze the inheritance for a son

For a son, he gets the \(Y\) chromosome from the father. The probability of getting the \(Y\) chromosome from the father is 1. The mother can pass either \(X^B\) or \(X^b\) to the son. The probability of the mother passing the \(X^b\) allele to the son is \(\frac{1}{2}\).

Answer:

50%