Repetitive sequence are stretches of DNA with repeated bases many times of in a genome but.
(a) These sequence are of no transcriptional function.
(b) These are associated with euchromatin region .
(c) These helps to identify a person on the basis of its DNA specificity.

Options

A. All are correct
B. Only (b) is incorrect
C. Both (a) & (b) are correct
D. Both (b) & (c) are incorrect

Answer

To solve the question regarding repetitive sequences in DNA, we will analyze each statement provided in the question and determine whether they are true or false.

### Step-by-Step Solution:

1. **Understanding Repetitive Sequences**:
- Repetitive sequences are stretches of DNA that contain repeated base pairs. These sequences can be classified into different types, such as microsatellites and minisatellites.

2. **Evaluating Statement (a)**:
- **Statement**: "These sequences are of no transcriptional function."
- **Analysis**: This statement is true. Repetitive sequences, particularly those that are non-coding, do not have a direct role in coding for proteins and are generally considered to have no transcriptional function.

3. **Evaluating Statement (b)**:
- **Statement**: "These are associated with euchromatin region."
- **Analysis**: This statement is false. Repetitive sequences are typically found in heterochromatin regions, which are tightly packed and not actively transcribed. Euchromatin, on the other hand, is loosely packed and associated with active transcription.

4. **Evaluating Statement (c)**:
- **Statement**: "These help to identify a person on the basis of its DNA specificity."
- **Analysis**: This statement is true. Repetitive sequences, especially microsatellites, are used as genetic markers in forensic science and paternity testing to identify individuals based on their unique DNA profiles.

5. **Conclusion**:
- Based on the evaluations:
- Statement (a) is true.
- Statement (b) is false.
- Statement (c) is true.
- Therefore, the correct answer is that only statement (b) is incorrect.

### Final Answer:
The correct option is: **Only B is incorrect.**

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