Which is gentically not possible

Options

A. Haemophilic father transfers the haemophilic gene to his son
B. Haemophilic father transfers the haemophilic gene to his daughter
C. Carrier mother transfers the haemophilic gene to her son
D. Carrier mother transfers the haemophilic gene to her daughter

Answer

To determine which scenario is genetically not possible regarding hemophilia, we need to understand the inheritance pattern of this sex-linked disorder. Here’s a step-by-step breakdown of the question:

### Step-by-Step Solution:

1. **Understand Hemophilia**: Hemophilia is a genetic disorder that affects the blood's ability to clot and is typically inherited in a sex-linked manner, meaning the gene responsible for hemophilia is located on the X chromosome.

2. **Identify the Parents' Genotypes**:
- A hemophilic father has the genotype XhY (where Xh represents the X chromosome with the hemophilia allele).
- A carrier mother has the genotype XXh (where X represents a normal allele and Xh represents the hemophilia allele).

3. **Analyze Each Option**:
- **Option 1**: Hemophilic father transfers the hemophilic gene to his son.
- **Analysis**: The father can only pass on his Y chromosome to his son (XY). Therefore, he cannot pass the X chromosome (which carries the hemophilia gene) to his son. This scenario is genetically not possible.

- **Option 2**: Hemophilic father transfers the hemophilic gene to his daughter.
- **Analysis**: The father passes his X chromosome to his daughter (XXh). Thus, the daughter can inherit the hemophilia gene. This scenario is genetically possible.

- **Option 3**: Carrier mother transfers the hemophilic gene to her son.
- **Analysis**: The mother can pass either her X chromosome with the normal allele or the X chromosome with the hemophilia allele (XXh) to her son (XY). Therefore, this scenario is genetically possible.

- **Option 4**: Carrier mother transfers the hemophilic gene to her daughter.
- **Analysis**: The mother can pass on either of her X chromosomes to her daughter (XXh). Thus, the daughter can inherit the hemophilia gene. This scenario is genetically possible.

4. **Conclusion**: The only scenario that is genetically not possible is the first option: "hemophilic father transfers the hemophilic gene to his son."

### Final Answer:
**The genetically not possible scenario is: Hemophilic father transfers the hemophilic gene to his son.**

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