Probes are employed in

Options

A. Electrophoresis
B. Southern blotting
C. Colony hybridization
D. (2) and (3)

Answer

### Step-by-Step Solution:

1. **Understanding Probes**: Probes are short sequences of nucleic acids that can bind to specific complementary sequences in DNA or RNA. They are used in various molecular biology techniques to detect or quantify specific nucleic acid sequences.

2. **Introduction to Electrophoresis**: Electrophoresis is a laboratory technique used to separate charged molecules, such as nucleic acids (DNA and RNA) and proteins, based on their size and charge when an electric field is applied.

3. **Role of Probes in Electrophoresis**: Probes can be utilized in conjunction with electrophoresis to identify specific nucleic acid sequences after they have been separated. For example, after running a gel electrophoresis, probes can hybridize to the target DNA fragments, allowing for visualization or quantification.

4. **Types of Electrophoresis**: The most common form of electrophoresis used in molecular biology is gel electrophoresis, where molecules are separated through a gel matrix. This technique is widely used for analyzing DNA, RNA, and proteins.

5. **Conclusion**: Based on the understanding that probes are used in the context of electrophoresis for the detection and analysis of nucleic acids, we conclude that probes are indeed employed in electrophoresis.

### Final Answer:
Probes are employed in electrophoresis.

---