Which of the following statement is incorrect regarding the band region of polytene chromosome ?

Options

A. Feulgen nagative area
B. Absorb ultraviolet light at 2600 `Å`
C. Chromonemata is tightly packed
D. Stain intensity with basic stain

Answer

To solve the question regarding the incorrect statement about the band region of polytene chromosomes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Polytene Chromosomes**:
- Polytene chromosomes are giant chromosomes that are primarily found in the salivary glands of certain insects, particularly dipterans (like fruit flies).
- They are formed by the replication of DNA without cell division, leading to multiple copies of the chromosome.

**Hint**: Remember that polytene chromosomes are associated with specific tissues in certain organisms.

2. **Characteristics of Polytene Chromosomes**:
- These chromosomes are euchromatic in nature, meaning they are less condensed and actively involved in transcription.
- They contain a large amount of genes, along with some RNA and basic proteins.

**Hint**: Focus on the nature of the chromatin and its components.

3. **Structure of Polytene Chromosomes**:
- Polytene chromosomes are divided into dark bands and interbands.
- Dark bands are regions that stain positively, while interbands stain negatively.

**Hint**: Pay attention to how these bands are visualized under a microscope.

4. **Staining Properties**:
- The bands of polytene chromosomes are stained by fluorescein, making them fluorescein positive.
- This means that the dark bands will show a positive reaction to fluorescein staining.

**Hint**: Consider the staining techniques used in cytogenetics.

5. **Evaluate the Options**:
- Based on the characteristics described, we need to identify the incorrect statement from the provided options.
- The statement that indicates the bands are fluorescein negative would be incorrect, as they are known to be fluorescein positive.

**Hint**: Cross-check each statement against the known properties of polytene chromosomes.

6. **Conclusion**:
- The incorrect statement regarding the band region of polytene chromosomes is that they are fluorescein negative. All other statements about their properties are correct.

**Final Answer**: The incorrect statement is that the band is fluorescein negative.