Red eyed female Drosophila is crossed with white eyed male. If this cross results in 50% progeny being red eyed, we can say that -

Options

A. Both parents were hemizygous
B. Female parent was heterozygous
C. Female parent was pure
D. Both parents were pure

Answer

To solve the question regarding the cross between a red-eyed female Drosophila and a white-eyed male, we can follow these steps:

### Step 1: Identify the Genotypes
- The red-eyed female Drosophila can be either homozygous dominant (RR) or heterozygous (Rr) for the red eye trait.
- The white-eyed male Drosophila must be homozygous recessive (rr) since white eyes are a recessive trait.

### Step 2: Set Up the Cross
- Let's denote the red eye allele as "R" (dominant) and the white eye allele as "r" (recessive).
- If the female is heterozygous (Rr), the cross would be:
- Female: Rr (red-eyed)
- Male: rr (white-eyed)

### Step 3: Perform the Punnett Square
- Set up a Punnett square for the cross Rr x rr:

| | r | r |
|-----|-----|-----|
| **R** | Rr | Rr |
| **r** | rr | rr |

### Step 4: Analyze the Results
- From the Punnett square, we see the following genotypes in the progeny:
- 50% Rr (red-eyed)
- 50% rr (white-eyed)

### Step 5: Conclusion
- Since the cross results in 50% of the progeny being red-eyed and 50% being white-eyed, we conclude that the red-eyed female must be heterozygous (Rr).
- Therefore, we can say that the red-eyed female Drosophila is heterozygous for the red eye trait.

### Final Statement
- The answer to the question is: The red-eyed female Drosophila is heterozygous (Rr).

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