The offspring of AA bb `xx` aa BB is crossed with , aabb. The genotypic ratio of progeny will be

Options

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

Answer

To solve the problem of determining the genotypic ratio of the progeny from the cross between AA bb xx aa BB and aabb, we will follow these steps:

### Step 1: Identify the Genotypes of the Parents
- The first parent has the genotype **AA bb xx aa BB**. However, since we are only interested in the alleles that will segregate, we can simplify this to **AA bb** (as xx does not contribute to the gametes).
- The second parent has the genotype **aabb**.

### Step 2: Determine the Gametes Produced by Each Parent
- The first parent (AA bb) can produce the following gametes:
- Since it is homozygous for A (AA), it can only produce **A**.
- For the b allele, it is homozygous recessive (bb), so it can only produce **b**.

Therefore, the gametes from the first parent are: **Ab**.

- The second parent (aabb) can produce the following gametes:
- It is homozygous recessive for both traits, producing **a** and **b**.

Therefore, the gametes from the second parent are: **ab**.

### Step 3: Set Up the Punnett Square
Now we can set up a Punnett square to visualize the offspring from the cross of the two gametes:
- Parent 1 gametes: **Ab**
- Parent 2 gametes: **ab**

| | Ab |
|------|------|
| ab | AaBb |

### Step 4: Determine the Genotypes of the Progeny
From the Punnett square, we can see that the resulting genotype of the offspring is:
- **AaBb**

### Step 5: Calculate the Genotypic Ratio
Since there is only one genotype produced from this cross, the genotypic ratio of the progeny is:
- **1 AaBb**

### Final Answer
The genotypic ratio of the progeny will be **1:0** (1 AaBb and no other genotypes).

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