What fraction of offsprings would have the genotype AA Bb Cc in `F_(2)` generation of a trihybrid cross -

Options

A. 0.125
B. 0.0625
C. 0.25
D. 0.375

Answer

To find the fraction of offspring with the genotype AA Bb Cc in the F2 generation of a trihybrid cross, we can follow these steps:

### Step 1: Understand the Cross
In a trihybrid cross, we are dealing with three traits (genes) that segregate independently. In this case, we are looking at three genes: A, B, and C.

### Step 2: Determine the Genotypes
We are interested in the genotype AA Bb Cc.
- For gene A, we want the genotype AA.
- For gene B, we want the genotype Bb.
- For gene C, we want the genotype Cc.

### Step 3: Analyze Each Gene Separately
We will analyze the inheritance of each gene separately using a Punnett square.

#### Gene A (AA)
- The cross for gene A is AA x AA.
- The possible offspring genotypes are:
- AA (100%)

So, the fraction for AA is 1 (or 100%).

#### Gene B (Bb)
- The cross for gene B is Bb x Bb.
- The possible offspring genotypes are:
- BB (1/4)
- Bb (1/2)
- bb (1/4)

So, the fraction for Bb is 1/2.

#### Gene C (Cc)
- The cross for gene C is Cc x Cc.
- The possible offspring genotypes are:
- CC (1/4)
- Cc (1/2)
- cc (1/4)

So, the fraction for Cc is 1/2.

### Step 4: Multiply the Fractions
Now, we multiply the fractions of each gene together to find the fraction of offspring with the genotype AA Bb Cc.

\[ \text{Fraction} = \text{Fraction of AA} \times \text{Fraction of Bb} \times \text{Fraction of Cc} \]
\[ \text{Fraction} = 1 \times \frac{1}{2} \times \frac{1}{2} = \frac{1}{4} \]

### Step 5: Convert to Decimal
To express this fraction as a decimal:
\[ \frac{1}{4} = 0.25 \]

### Conclusion
The fraction of offspring with the genotype AA Bb Cc in the F2 generation of a trihybrid cross is **0.25** or **25%**.

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