Which one is a fertile hybrid ?

Options

A. Mule
B. Hinny
C. Both A and B
D. Liger.

Answer

To determine which one is a fertile hybrid among the given options (mule, hinny, both A and B, and liger), we need to analyze the fertility of each hybrid.

### Step-by-Step Solution:

1. **Understanding Hybrids**:
- A hybrid is the offspring produced from the mating of two different species or subspecies. In this case, we have three hybrids to consider: mule, hinny, and liger.

2. **Identifying the Hybrids**:
- **Mule**: A mule is the offspring of a male donkey (62 chromosomes) and a female horse (64 chromosomes). Mules have a total of 63 chromosomes.
- **Hinny**: A hinny is the offspring of a female donkey and a male horse. Like mules, hinnies also have 63 chromosomes.
- **Liger**: A liger is the offspring of a male lion and a female tiger.

3. **Chromosome Count and Fertility**:
- Both mules and hinnies have 63 chromosomes, which is an odd number. This odd number of chromosomes usually prevents proper pairing during meiosis, leading to infertility. Therefore, both mules and hinnies are generally infertile.
- In contrast, ligers can have different fertility outcomes. Male ligers are typically sterile, but female ligers can be fertile.

4. **Applying Haldane's Rule**:
- Haldane's rule states that in hybrids, if one sex is absent or sterile, it is usually the heterogametic sex (the sex with two different sex chromosomes). In the case of ligers, male ligers (the heterogametic sex) are sterile, while females can reproduce.

5. **Conclusion**:
- Since mules and hinnies are both infertile hybrids, and female ligers are fertile, the correct answer to the question "Which one is a fertile hybrid?" is **liger**.

### Final Answer:
The fertile hybrid among the options is **liger**.