The following are used as genetic markers

Options

A. RFLPS
B. Repeated sequences
C. STRs
D. All the above

Answer

To solve the question regarding which options are used as genetic markers, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Genetic Markers**:
- A genetic marker is a specific DNA sequence that can be identified and is located at a known position on a chromosome. These markers are used in various genetic analyses, including mapping genes and studying genetic diversity.

2. **Analyze the Options Provided**:
- The question provides several options that may represent genetic markers. We need to evaluate each option to determine if it qualifies as a genetic marker.

3. **Evaluate Each Option**:
- **Option 1: RFLP (Restriction Fragment Length Polymorphism)**:
- RFLP is a technique that exploits variations in homologous DNA sequences. It involves the digestion of DNA with restriction enzymes and the analysis of the resulting fragment lengths. RFLPs are indeed used as genetic markers.

- **Option 2: Repeated Sequences (VNTR - Variable Number Tandem Repeat)**:
- VNTRs are sequences of DNA that repeat a certain number of times. The number of repeats can vary among individuals, making VNTRs useful as genetic markers in forensic analysis and paternity testing.

- **Option 3: STR (Short Tandem Repeat)**:
- STRs are similar to VNTRs but consist of shorter repeat units. They are commonly used in genetic profiling and are also considered genetic markers.

4. **Conclusion**:
- Since RFLP, VNTR, and STR are all recognized as genetic markers, the correct answer to the question is that all the options provided (RFLP, VNTR, and STR) are used as genetic markers. Therefore, the answer is **Option D: All of the above**.

### Final Answer:
All the options listed (RFLP, VNTR, and STR) are used as genetic markers. The answer is **Option D: All of the above**.

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