A woman whose mother was colourblind and father was haemophilic , marries a colourblind haemophilic man . What is true about their daughters ?

Options

A. All their daughters are colourblind and haemophilic
B. They may have daughters who neither suffer from colourblindness nor from haemophilia
C. They may have daughters who are colourblind or haemophilic
D. Some of their daughters are colourblind but not haemophilic

Answer

To solve the problem, we need to analyze the genetic conditions of the individuals involved and how they affect their daughters.

### Step 1: Understand the Genetic Conditions
1. **Colorblindness** is an X-linked recessive trait. This means that a female needs two copies of the colorblind allele (XcXc) to express the trait, while a male only needs one (XcY).
2. **Hemophilia** is also an X-linked recessive trait. Similar to colorblindness, a female needs two copies of the hemophilia allele (XhXh) to express the trait, while a male only needs one (XhY).

### Step 2: Determine the Genotypes of the Parents
- The woman has a colorblind mother and a hemophilic father.
- Her mother (colorblind) would have the genotype XcXc.
- Her father (hemophilic) would have the genotype XhY.
- Therefore, the woman must be a carrier for both traits: XcXh (since she inherits one X chromosome from each parent).

- The man is both colorblind and hemophilic.
- His genotype is XcY (colorblind) and XhY (hemophilic), which means he has the genotype XcXhY.

### Step 3: Determine the Possible Genotypes of Their Daughters
When the woman (XcXh) and the man (XcY) have daughters, we can set up a Punnett square to determine the possible genotypes of their daughters:

| | Xc (from father) | Y (from father) |
|-----|-------------------|------------------|
| Xc (from mother) | XcXc (colorblind) | XcY (colorblind) |
| Xh (from mother) | XhXc (carrier) | XhY (hemophilic) |

From this, we can see the possible genotypes for their daughters:
1. XcXc (colorblind)
2. XcXh (carrier for hemophilia, not colorblind)
3. XhXc (carrier for colorblindness, hemophilic)

### Step 4: Analyze the Options
Now let's analyze the options given in the question:
- **A. All their daughters are colorblind and hemophilic.** - Incorrect, as not all daughters will have both conditions.
- **B. They may have daughters who neither suffer from colorblindness nor from hemophilia.** - Incorrect, as all daughters will either be colorblind or hemophilic.
- **C. They may have daughters who are colorblind or hemophilic.** - Correct, as we have seen that daughters can be colorblind or hemophilic.
- **D. Some of their daughters are colorblind but not hemophilic.** - Incorrect, as some daughters will be hemophilic.

### Conclusion
The correct answer is **C. They may have daughters who are colorblind or hemophilic.**