Identify correct statement w.r.t. fruit fly.

Options

A. Chromosomal theory of inheritance was proposed by using it
B. Shows ZO-ZZ type of sex determination
C. Recombination between white eye and miniature wings was `37.2%`
D. more than one option is correct

Answer

To identify the correct statement regarding fruit flies (Drosophila melanogaster), we can analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understand the Context**: Fruit flies, scientifically known as Drosophila melanogaster, are widely used as model organisms in genetic research. They have been instrumental in studying inheritance patterns and genetic linkage.

2. **Evaluate the Statements**:
- **Statement 1**: Claims that the chromosomal theory of inheritance was proposed using fruit flies.
- **Analysis**: The chromosomal theory of inheritance was proposed by Sutton and Boveri based on cytological observations of chromosomes during meiosis. Although Drosophila was used by Morgan to verify this theory, it was not the organism used to propose it. Thus, this statement is incorrect.

- **Statement 2**: States that Drosophila has Z-O-Z-Z sex determination similar to humans, where males have XY chromosomes and females have XX chromosomes.
- **Analysis**: This statement is incorrect as Drosophila exhibits XY sex determination, similar to humans, not Z-O-Z-Z.

- **Statement 3**: Mentions a recombination frequency of 37.2% between the white eye and miniature wing traits.
- **Analysis**: This statement is correct. Morgan's experiments on Drosophila showed that genes located close together on the same chromosome do not assort independently, leading to a reduced recombination frequency of 37.2% between the genes for white eye color and miniature wings.

3. **Conclusion**: After evaluating all the statements, the correct statement regarding fruit flies is **Statement 3**, which discusses the recombination frequency between the white eye and miniature wing traits.

### Final Answer:
The correct statement with respect to fruit fly (Drosophila melanogaster) is that the recombination frequency between the white eye and miniature wing traits is 37.2%.

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