In which of the following female is heterogametic ?

Options

A. Drosophila
B. Human
C. Fowl
D. Honey bee

Answer

To determine which of the following females is heterogametic, we need to understand what heterogametic means. Heterogametic refers to individuals that produce two different types of gametes.

Let's analyze each option:

1. **Drosophila (fruit fly)**:
- In Drosophila, females have the genotype XX, meaning they produce only one type of gamete (X). Therefore, Drosophila females are not heterogametic.

2. **Humans**:
- In humans, females also have the genotype XX, while males have XY. Males produce two different types of gametes (X and Y), making them heterogametic. Thus, human females are not heterogametic.

3. **Fowl (birds)**:
- In fowl, the females have the genotype ZW, while the males have ZZ. Since females produce two different types of gametes (Z and W), fowl females are heterogametic.

4. **Honeybee**:
- In honeybees, females are diploid (having two sets of chromosomes) and typically have the genotype XX, while males are haploid (having one set of chromosomes) and have the genotype X. Therefore, honeybee females are not heterogametic.

Based on this analysis, the correct answer is that the female that is heterogametic is found in **fowl (option 3)**.

### Summary of the Solution Steps:
1. Define heterogametic: Individuals that produce two different types of gametes.
2. Analyze Drosophila: Females are XX (homogametic).
3. Analyze Humans: Females are XX (homogametic).
4. Analyze Fowl: Females are ZW (heterogametic).
5. Analyze Honeybee: Females are XX (homogametic).
6. Conclude that the female that is heterogametic is in **fowl (option 3)**.