In which of the process is both the DNA strand transcribed ?

Options

A. PCR
B. DNA replication
C. RNAi
D. Southern blotting

Answer

To solve the question "In which of the processes is both the DNA strands transcribed?", we will analyze the options provided and understand the concept of transcription.

### Step-by-Step Solution:

1. **Understanding Transcription**:
- Transcription is the process where a specific segment of DNA is copied into RNA. This process is facilitated by the enzyme RNA polymerase.

2. **Identifying the Processes**:
- We need to evaluate the given options to determine which one involves the transcription of both DNA strands.

3. **Evaluating Each Option**:
- **Option 1: DNA Replication**:
- In DNA replication, the DNA is copied to produce two identical DNA molecules. This process does not involve the formation of RNA, so it is not the correct answer.

- **Option 2: PCR (Polymerase Chain Reaction)**:
- PCR is a technique used to amplify specific DNA segments. It does not involve transcription (DNA to RNA conversion), thus this option is also incorrect.

- **Option 3: Southern Blotting**:
- Southern blotting is a method used to detect specific DNA sequences in samples. It does not involve transcription either, making this option incorrect.

- **Option 4: RNAi (RNA Interference)**:
- RNA interference is a biological process where double-stranded RNA (dsRNA) leads to the silencing of gene expression. This dsRNA is generated from double-stranded DNA through transcription. Therefore, this process involves the transcription of both strands of DNA, making it the correct answer.

4. **Conclusion**:
- Based on the analysis, the correct answer is **RNAi (RNA Interference)**, as it is the only process where both DNA strands are transcribed to produce RNA.

### Final Answer:
**RNAi (RNA Interference)** is the process in which both DNA strands are transcribed.