During a dihybrid cross in the `F_(2)` generation, the ratio of inidviduals showing one dominant and other recessive character will be ……… of parents with contrasting characters

Options

A. `4//16`
B. `6//16`
C. `8//16`
D. `9//16`

Answer

To solve the question regarding the dihybrid cross in the F2 generation, we can follow these steps:

### Step 1: Understand the Dihybrid Cross
A dihybrid cross involves two traits, each with two alleles. For example, let's consider two traits: seed shape (round vs. wrinkled) and seed color (yellow vs. green). The dominant traits are round (R) and yellow (Y), while the recessive traits are wrinkled (r) and green (y).

### Step 2: Determine the Parental Generation
In a typical dihybrid cross, the parental generation (P) consists of individuals that are homozygous for both traits. For example:
- Parent 1: RRYY (round and yellow)
- Parent 2: rryy (wrinkled and green)

### Step 3: F1 Generation
When these parents are crossed, all offspring in the F1 generation will be heterozygous for both traits (RrYy), displaying the dominant phenotypes (round and yellow).

### Step 4: F2 Generation
When the F1 individuals are crossed (RrYy x RrYy), the F2 generation is produced. The phenotypic ratio of the F2 generation from a dihybrid cross is typically 9:3:3:1.
- 9 individuals show both dominant traits (round and yellow).
- 3 individuals show the dominant trait for the first character and the recessive trait for the second character (round and green).
- 3 individuals show the recessive trait for the first character and the dominant trait for the second character (wrinkled and yellow).
- 1 individual shows both recessive traits (wrinkled and green).

### Step 5: Calculate the Ratio of One Dominant and One Recessive Trait
From the F2 generation, we focus on the individuals showing one dominant and one recessive trait. This includes:
- 3 individuals with round and green (dominant for shape, recessive for color).
- 3 individuals with wrinkled and yellow (recessive for shape, dominant for color).

Thus, the total number of individuals showing one dominant and one recessive trait is 3 + 3 = 6.

### Step 6: Express the Ratio
The total number of offspring in the F2 generation is 16 (from the 9:3:3:1 ratio). Therefore, the ratio of individuals showing one dominant and one recessive trait is:
\[ \frac{6}{16} \]
This can be simplified to:
\[ \frac{3}{8} \]

### Final Answer
The ratio of individuals showing one dominant and one recessive character in the F2 generation of a dihybrid cross is \( \frac{6}{16} \) or \( \frac{3}{8} \).

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