A color - blind man marries a woman who is carrier for hemophilia . Which of the following is true for their progenies ?

Options

A. 25% of the progenies carry the genes for both hemophilia and color - blindness
B. 25% of the progenies carry only the gene for hemophilia
C. 25% of the progenies carry only the gene for color - blindness
D. All of these

Answer

To solve the problem of determining the genetic outcomes for the progeny of a color-blind man and a woman who is a carrier for hemophilia, we can follow these steps:

### Step 1: Understand the Genetic Background
- Color blindness is a sex-linked recessive trait carried on the X chromosome. A color-blind man has the genotype **XcY**, where **Xc** represents the X chromosome with the color blindness allele.
- Hemophilia is also a sex-linked recessive trait, also carried on the X chromosome. A woman who is a carrier for hemophilia has the genotype **XHXh**, where **XH** is the normal allele and **Xh** is the allele for hemophilia.

### Step 2: Set Up the Punnett Square
To determine the possible genotypes of their offspring, we can set up a Punnett square using the genotypes of the parents:

- Male: **XcY**
- Female: **XHXh**

The possible gametes from each parent are:
- From the color-blind man: **Xc** and **Y**
- From the carrier woman: **XH** and **Xh**

### Step 3: Fill in the Punnett Square
Now we can fill in the Punnett square:

| | XH | Xh |
|---------|----------|----------|
| **Xc** | XHXc | XhXc |
| **Y** | XHY | XhY |

### Step 4: Analyze the Results
From the Punnett square, we can identify the possible genotypes of the offspring:
1. **XHXc** - Female, carrier for hemophilia, normal vision (25%)
2. **XhXc** - Female, carrier for both hemophilia and color blindness (25%)
3. **XHY** - Male, normal vision, not hemophilic (25%)
4. **XhY** - Male, color blind, hemophilic (25%)

### Step 5: Conclusion
The progeny will have the following probabilities:
- 25% will be females who are carriers for hemophilia and have normal vision.
- 25% will be females who are carriers for both hemophilia and color blindness.
- 25% will be males with normal vision.
- 25% will be males who are color blind and hemophilic.

Thus, the correct answer is that all of the statements about the progeny are true.