Which of the following description of eye colour is true for fruit fly ?

Options

A. White eye colour is dominant over red eye colour and its gene is located on autosome .
B. Red eye colour dominant over red eye colour and its gene is located on autosome
C. White eye colour is dominant over red eye colour and its gene is located on the X chromosome .
D. Red eye colour dominant over red eye colour and its gene is located on the X chromosome .

Answer

To solve the question regarding the eye color of fruit flies, we can follow these steps:

### Step 1: Understand the Basics of Eye Color in Fruit Flies
- In fruit flies (Drosophila melanogaster), the wild type eye color is red.
- The red eye color is dominant over the white eye color.

**Hint:** Remember that dominant traits mask the presence of recessive traits.

### Step 2: Identify the Genetic Basis
- The genes responsible for eye color in fruit flies are located on the X chromosome.
- This means that the inheritance of eye color is X-linked.

**Hint:** X-linked traits are passed down through the X chromosome, which is crucial for understanding inheritance patterns.

### Step 3: Analyze the Options
- The options provided in the question describe various relationships between the eye colors and their genetic locations.
- We need to determine which statement correctly reflects the dominance and location of the genes.

**Hint:** Look for the option that states that red is dominant over white and that the gene is located on the X chromosome.

### Step 4: Evaluate Each Option
1. **First Option:** Claims white is dominant over red. This is incorrect.
2. **Second Option:** States red is dominant but incorrectly claims the gene is on an autosome. This is incorrect.
3. **Third Option:** Claims white is dominant, which is incorrect.
4. **Fourth Option:** Correctly states that red is dominant over white and that the gene is located on the X chromosome.

**Hint:** Eliminate options that contradict the established dominance and genetic location.

### Step 5: Conclusion
- The correct description of eye color in fruit flies is found in the fourth option, which states that red eye color is dominant over white and that the gene is located on the X chromosome.

**Final Answer:** The correct description is that red eye color is dominant over white and its genes are located on the X chromosome.