Gene expression can be controlled with the help of RNA. Explain the method with an example.

Explanation

**Step-by-Step Solution:**

1. **Understanding Gene Expression Control**: Gene expression refers to the process by which information from a gene is used to synthesize functional gene products, typically proteins. Controlling gene expression is crucial for regulating various biological processes.

2. **Introduction to RNA Interference (RNAi)**: One of the methods to control gene expression is through RNA interference (RNAi). RNAi is a biological process in which RNA molecules inhibit gene expression or translation, effectively silencing targeted genes.

3. **Mechanism of RNAi**: In RNA interference, a complementary RNA strand binds to messenger RNA (mRNA). This binding prevents the mRNA from being translated into a protein. The process involves small RNA molecules, such as small interfering RNA (siRNA) or microRNA (miRNA), which are crucial for the silencing process.

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