lf vestigial winged female Drosophila, heterozygous for long wing, the possibel phenotypic ratio is

Options

A. `9:3:3:1`
B. `1:2:2:4`
C. `1:1:1:1`
D. `1:2:1:2`

Answer

To solve the problem of determining the possible phenotypic ratio of a cross between a vestigial winged female Drosophila and a heterozygous long-winged male, we can follow these steps:

### Step 1: Identify the Genotypes
- The vestigial winged female Drosophila is homozygous recessive for the wing trait, represented as **ll** (where "l" stands for the vestigial wing allele).
- The heterozygous long-winged male Drosophila has one dominant allele for long wings and one recessive allele for vestigial wings, represented as **Ll**.

### Step 2: Set Up the Cross
- We will set up a Punnett square to visualize the cross between the two genotypes:
- Female (vestigial): **ll**
- Male (heterozygous long-wing): **Ll**

### Step 3: Fill in the Punnett Square
- The possible gametes from the female (ll) are: **l** and **l**.
- The possible gametes from the male (Ll) are: **L** and **l**.

Now we can fill in the Punnett square:

| | L | l |
|-------|-------|-------|
| **l** | Ll | ll |
| **l** | Ll | ll |

### Step 4: Determine the Offspring Genotypes
- From the Punnett square, we can see the following genotypes:
- **Ll** (long-winged) - 2 occurrences
- **ll** (vestigial-winged) - 2 occurrences

### Step 5: Calculate the Phenotypic Ratio
- The phenotypes corresponding to the genotypes are:
- Long-winged (from Ll) = 2
- Vestigial-winged (from ll) = 2

Thus, the phenotypic ratio is:
- Long-winged : Vestigial-winged = 2 : 2, which simplifies to **1 : 1**.

### Final Answer
The possible phenotypic ratio of the offspring from this cross is **1:1**.

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