Question

what is the probability of the offspring having red - green color blindness for the cross that is represented by the punnett square?
0 percent
25 percent
50 percent
75 percent

Explanation:

Step1: Determine the genotypes of parents

Assume the cross is \(X^{B}X^{b}\) (female, carrier) and \(X^{B}Y\) (male, normal). The Punnett - square columns are \(X^{B}\) and \(Y\) (from male), rows are \(X^{B}\) and \(X^{b}\) (from female).

Step2: Fill in the Punnett - square

The four genotypes of offspring are \(X^{B}X^{B}\), \(X^{B}Y\), \(X^{B}X^{b}\), \(X^{b}Y\).

Step3: Identify color - blind genotypes

Red - green color blindness is X - linked recessive. The color - blind genotype is \(X^{b}Y\).

Step4: Calculate the probability

There are 4 possible genotypes. The number of color - blind genotypes (\(X^{b}Y\)) is 1. Probability \(P=\frac{1}{4}=0.25 = 25\%\)

Answer:

25 percent