Detection of a clone is done by

Options

A. gel electrophoresis
B. autoradiography
C. PCR
D. all of these

Answer

To answer the question "Detection of a clone is done by?", we can analyze the options provided and understand the techniques involved in detecting clones.

### Step-by-Step Solution:

1. **Understanding Cloning**: Cloning refers to the process of creating a genetically identical copy of an organism or a cell. In biotechnology, it often involves the replication of DNA segments.

2. **Option Analysis**:
- **Gel Electrophoresis**: This technique is used to separate DNA fragments based on their size. It can help in visualizing the presence of specific DNA fragments, but it does not directly indicate whether a clone has been successfully created.
- **Auto Radiography**: This technique involves using X-ray film to detect radioactive labels on DNA. It can be used to visualize cloned DNA fragments, making it a viable method for detecting clones.
- **PCR (Polymerase Chain Reaction)**: PCR is a method used to amplify specific DNA sequences, allowing for the production of millions of copies of a particular DNA segment. While PCR is crucial for cloning, it is not a direct method for detecting clones.
- **All of These**: This option suggests that all the mentioned techniques can be used for detection.

3. **Conclusion**: Among the options, Auto Radiography is specifically mentioned as a method for detecting clones. While Gel Electrophoresis and PCR are important techniques in the cloning process, they do not serve primarily as detection methods. Therefore, the most appropriate answer is Auto Radiography.

### Final Answer:
Detection of a clone is done by **Auto Radiography**.