If the nuclei from an 8–celled stage of an embryo are transplanted into enucleated eggs, which of the following events is likely to occur

Options

A. Formation of viable embryo in the recipient eggs
B. Donor nuclei die in the new environment
C. Cleavage occurs but is arrested after some time
D. Recipient egg dies

Explanation

To answer the question regarding the transplantation of nuclei from an 8-celled stage of an embryo into enucleated eggs, we can analyze the potential outcomes step by step.

### Step-by-Step Solution:

1. **Understanding the Components**:
- An 8-celled stage of an embryo consists of cells that are already undergoing development. Each of these cells contains a nucleus that holds genetic material.
- Enucleated eggs are eggs from which the nucleus has been removed. This means they lack the genetic material required for development.

2. **Transplantation Process**:
- When the nuclei from the 8-celled embryo are transplanted into the enucleated eggs, the eggs now contain the genetic material from the donor embryo.

3. **Potential Outcomes**:
- **Formation of a Viable Embryo**: If the transplanted nuclei can successfully integrate and reprogram the enucleated egg, there is a possibility that a viable embryo could form. This would depend on the compatibility of the donor nuclei with the egg cytoplasm.
- **Cleavage Occurs but is Arrested**: In some cases, the egg may begin to divide (cleavage) due to the presence of the new nucleus, but the process may halt if the egg cannot support further development.
- **Recipient Egg Dies**: It is also possible that the enucleated egg may not survive the transplantation process or may not be able to support the new nucleus, leading to cell death.
- **E-nucleated Egg Develops into Mature Embryo**: This outcome is unlikely unless the egg can fully reprogram and support the new nucleus, which is a complex process.

4. **Conclusion**:
- The most likely event that occurs when nuclei from an 8-celled stage of an embryo are transplanted into enucleated eggs is that cleavage occurs but may be arrested after some time. This is due to the challenges in reprogramming and supporting the new nucleus in the egg.

### Final Answer:
Cleavage occurs but is arrested after some time.