Genes can be inserted into human cells by

Options

A. PCR
B. Xenotransplantation
C. Modified viruses
D. Modified microarrays

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how genes can be inserted into human cells. This involves identifying methods or techniques that facilitate the introduction of genetic material into cells.

2. **Analyzing the Options**:
- **Option A: PCR (Polymerase Chain Reaction)**: PCR is a technique used to amplify DNA, meaning it creates multiple copies of a specific DNA segment. However, it does not involve the insertion of genes into cells. Therefore, this option is incorrect.

- **Option B: Xenotransplantation**: This refers to the transplantation of organs or tissues from one species to another. While it involves the introduction of foreign biological material, it does not specifically pertain to the insertion of genes into human cells. Thus, this option is also incorrect.

- **Option C: Modified Viruses**: Modified viruses can be used as vectors to deliver genes into human cells. These viruses are engineered to be safe and can effectively introduce genetic material into the cells. This method is widely used in gene therapy, making this option correct.

- **Option D: Modified Microarrays**: Microarrays are tools used to study gene expression and do not involve the insertion of genes into cells. They are used for analyzing the expression levels of multiple genes simultaneously. Hence, this option is incorrect.

3. **Conclusion**: After analyzing all the options, the correct answer is **Option C: Modified Viruses**, as they can be used to insert genes into human cells effectively.

**Final Answer**: Genes can be inserted into human cells by **modified viruses**.

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