When a transgene is introduced into the genome of an organism, its expression can achieve which of the follow- ing?

Options

A. Produces a protein that is the product in which we are interested
B. Prevents the expression of existing natural gene
C. Modifies the existing biosynthetic pathway so that a new-end product is obtained
D. All of these

Answer

To answer the question regarding the expression of a transgene when introduced into the genome of an organism, we can analyze the possible outcomes step by step.

### Step-by-Step Solution:

1. **Understanding Transgenes**: A transgene is a gene that has been transferred from one organism to another, often from a different species. The introduction of a transgene into an organism's genome can lead to various outcomes depending on how it interacts with the host's genetic material.

2. **Option 1: Produces a Protein of Interest**:
- When a transgene is expressed, it can produce a protein that the researchers are interested in. For example, in transgenic cows, the inserted human gene allows the cow to produce human proteins in its milk, which is a product of interest.
- **Conclusion**: This option is correct.

3. **Option 2: Prevents Expression of Existing Natural Gene**:
- The introduction of a transgene can sometimes suppress or prevent the expression of a natural gene. For instance, in the case of the transgenic cow, the expression of the human protein may inhibit the production of certain natural cow proteins.
- **Conclusion**: This option is also correct.

4. **Option 3: Modifies Existing Biosynthetic Pathway**:
- The introduction of a transgene can alter the existing biosynthetic pathways in the organism. For example, in the transgenic cow, the normal pathway for producing cow milk proteins is modified to produce human proteins instead.
- **Conclusion**: This option is correct as well.

5. **Final Conclusion**:
- Since all the options presented (producing a protein of interest, preventing the expression of existing genes, and modifying biosynthetic pathways) are valid outcomes of introducing a transgene, the correct answer is "all of these."

### Final Answer:
**All of these** (produces a protein of interest, prevents expression of existing natural gene, modifies existing biosynthetic pathway).

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