Answered

Discover answers to your questions with Westonci.ca, the leading Q&A platform that connects you with knowledgeable experts. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Color-deficient vision is a sex-linked recessive trait in humans. Parents with the following genotypes have a child:

[tex] X^R X^r \times X^R Y [/tex]

What is the probability that the child will have color-deficient vision?

A. 0.75
B. 0.50
C. 0.25
D. 1.00


Sagot :

Let's analyze the genotypes of the parents and the possible outcomes for their offspring.

1. Mother's Genotype: \(X^R X^r\)
- The mother is a carrier for the color-deficient vision gene.
- She carries one normal vision allele (\(X^R\)) and one color-deficient vision allele (\(X^r\)).

2. Father's Genotype: \(X^R Y\)
- The father has normal vision and carries one normal vision allele (\(X^R\)) and one Y chromosome.

To determine the possible genotypes of the offspring, we can set up a Punnett square. The potential combinations of the alleles from each parent are as follows:

| Mother \(X^R\) | Mother \(X^r\) |
|:--------------:|:-------------:|
| Father \(X^R\) | Father \(X^R\) |

Here are the potential genotypes of the offspring:

- From \(X^R\) (mother) and \(X^R\) (father): \(X^R X^R\) - Normal Vision (female)
- From \(X^r\) (mother) and \(X^R\) (father): \(X^R X^r\) - Carrier (female, but with normal vision)
- From \(X^R\) (mother) and \(Y\) (father): \(X^R Y\) - Normal Vision (male)
- From \(X^r\) (mother) and \(Y\) (father): \(X^r Y\) - Color-deficient vision (male)

Now, let's list the possible combinations and count them:
1. \(X^R X^R\) - female with normal vision
2. \(X^R X^r\) - female carrier with normal vision
3. \(X^R Y\) - male with normal vision
4. \(X^r Y\) - male with color-deficient vision

Out of these 4 combinations, only one results in a child with color-deficient vision (\(X^r Y\)).

The probability that the child will have color-deficient vision is calculated by dividing the favorable outcomes by the total possible outcomes:
[tex]\[ \frac{\text{Number of outcomes for color-deficient vision}}{\text{Total number of outcomes}} = \frac{1}{4} = 0.25 \][/tex]

Thus, the probability that the child will have color-deficient vision is:
[tex]\[ \boxed{0.25} \][/tex]

Therefore, the answer is:
C. 0.25