Dolly sheep was obtained by

Options

A. Cloning the udder cell (somatic cell) fused with unnucleated oocyte
B. Cloning of gametes
C. Tissue culture
D. None

Answer

**Step-by-Step Solution:**

1. **Understanding Cloning**: Cloning is a process where an organism is created that is genetically identical to another organism. This involves producing a copy of the DNA from the parent organism.

2. **Identifying the Source Cell**: In the case of Dolly the sheep, the source cell used for cloning was an udder cell from the donor sheep. This udder cell is a type of somatic cell, which means it is any cell of the body that is not a sperm or egg cell.

3. **Nucleus Transfer**: The nucleus of the udder cell, which contains the genetic material, was extracted and then fused with an enucleated oocyte (egg cell) from a surrogate mother. An enucleated oocyte is an egg cell that has had its nucleus removed, meaning it does not contain any genetic material.

4. **Fusion Process**: The process of fusion involves combining the somatic cell's nucleus with the enucleated oocyte. This creates a new cell that has the complete set of chromosomes from the udder cell, effectively making it a clone of the original sheep.

5. **Development of the Clone**: The fused cell is then stimulated to divide and develop into an embryo, which is implanted into the surrogate mother. The surrogate mother carries the embryo to term, resulting in the birth of Dolly.

6. **Conclusion**: Therefore, Dolly the sheep was obtained by cloning, specifically through the fusion of a somatic cell (udder cell) with an enucleated oocyte.

**Final Answer**: Dolly sheep was obtained by cloning the udder cell (somatic cell) fused with an enucleated oocyte.

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