An example of gene therapy is

Options

A. production of injectible hepatities B vaccine
B. production of vaccines in food crops like potatoes which can be eaten
C. introduction of gene for adenosine deaminase in persons suffering from SCID
D. production of test tube babies by artificial insemination and implantation of fertilised eggs

Answer

**Step-by-Step Solution:**

1. **Understanding Gene Therapy**: Gene therapy is a medical technique that aims to treat or prevent diseases by correcting defective genes. It involves replacing a faulty gene with a normal one to restore proper function.

2. **Identifying the Genetic Disorder**: One of the well-known genetic disorders that can be treated with gene therapy is Severe Combined Immunodeficiency (SCID), which is often caused by a deficiency in the enzyme adenosine deaminase (ADA).

3. **Evaluating the Options**:
- Option 1 discusses the production of an injectable hepatitis B vaccine, which is not an example of gene therapy.
- Option 2 mentions the production of vaccines in food crops, which also does not relate to gene therapy.
- Option 3 refers to the introduction of the gene for adenosine deaminase in individuals suffering from SCID, which is a correct application of gene therapy.
- Option 4 talks about the production of test tube babies, which is an assisted reproductive technology, not gene therapy.

4. **Conclusion**: The correct example of gene therapy from the provided options is the introduction of the gene for adenosine deaminase in persons suffering from SCID.

5. **Final Answer**: The correct answer is the introduction of the gene for adenosine deaminase in persons suffering from SCID.

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