Probes used in DNA finger printing are :

Options

A. highly sensitive electron microscope
B. UV beams
C. X-ray scanners
D. DNA segments having radioactive isotopes

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Fingerprinting**: DNA fingerprinting is a technique used to identify individuals based on their unique DNA profiles. It focuses on identifying variations in specific regions of DNA.

2. **Identifying Repetitive DNA**: In DNA fingerprinting, we analyze repetitive sequences of DNA, which are segments that are repeated multiple times. These are known as mini-satellites and micro-satellites.

3. **Role of Endonucleases**: To prepare the DNA for fingerprinting, we use enzymes called endonucleases. These enzymes cut the DNA at specific locations, allowing us to isolate the repetitive sequences.

4. **Probing with Radioactive DNA**: After digesting the DNA, we use probes to detect the specific DNA fragments. The probes used in DNA fingerprinting are typically radioactive DNA probes. These probes bind to the repetitive DNA sequences.

5. **Types of Probes**: The radioactive DNA probes are usually prepared from mini-satellites or micro-satellites, which are also referred to as Simple Sequence Repeats (SSRs) or Short Tandem Repeats (STRs). These are short sequences of 2 to 5 base pairs that are repeated.

6. **Conclusion**: Therefore, the probes used in DNA fingerprinting are DNA segments that have radioactive isotopes.

**Final Answer**: The probes used in DNA fingerprinting are DNA segments having radioactive isotopes.

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