Which of the following is not applicable to Drosophila

Options

A. Genes for maleness are located on autosomes
B. Genes for femaleness are located on X-chromosome
C. SRY gene codes for testies determining factor
D. Y-chromosome is essential for male fertility

Answer

To answer the question "Which of the following is not applicable to Drosophila?", we will analyze each statement provided in the options.

1. **Understanding Drosophila's Genetics**:
- Drosophila, particularly Drosophila melanogaster, is a model organism used extensively in genetic studies. It has a simple genetic structure comprising X and Y chromosomes, as well as autosomes.

2. **Analyzing Each Statement**:
- **Statement 1**: "Genes for maleness are located on autosomes."
- This statement is **true**. In Drosophila, genes that determine male characteristics are indeed located on the autosomes.

- **Statement 2**: "Genes for femaleness are located on X chromosome."
- This statement is **not entirely accurate**. While the X chromosome is involved in sex determination, it does not solely determine femaleness. It plays a broader role in sex determination rather than just being a carrier of female characteristics.

- **Statement 3**: "SRY gene encodes for testis-determining factor."
- This statement is **true**. The SRY gene, which is located on the Y chromosome, is responsible for the development of testes in males.

- **Statement 4**: "Y chromosome is essential for male fertility."
- This statement is **true**. The Y chromosome is important for sperm production, which is essential for male fertility.

3. **Conclusion**:
- Among the statements, the second statement is the one that is not applicable to Drosophila because it inaccurately describes the role of the X chromosome in determining femaleness.

**Final Answer**: The statement that is not applicable to Drosophila is: "Genes for femaleness are located on X chromosome."

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