The sum of genotype and phenotype possible in the Fe generation of test cross if parents are TTRRDDEE and ttrrddee

Options

A. 16
B. 32
C. 27
D. 64

Answer

To solve the question about the sum of genotype and phenotype possible in the F1 generation of a test cross involving the parents TTRRDDEE and ttrrddee, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Genotypes of the Parents**:
- The first parent has the genotype TTRRDDEE (homozygous dominant).
- The second parent has the genotype ttrrddee (homozygous recessive).

2. **Determine the Alleles Contributed by Each Parent**:
- The first parent contributes: T, R, D, E (all dominant alleles).
- The second parent contributes: t, r, d, e (all recessive alleles).

3. **Determine the Genotype of the F1 Generation**:
- When these parents are crossed, the F1 generation will be heterozygous for each trait:
- Genotype: TtRrDdEe

4. **Calculate the Number of Possible Genotypes**:
- Each gene pair (T/t, R/r, D/d, E/e) has 2 possible alleles (dominant and recessive).
- The total number of genotypes can be calculated using the formula \(2^n\), where \(n\) is the number of traits.
- Here, \(n = 4\) (T, R, D, E), so the number of genotypes is \(2^4 = 16\).

5. **Determine the Phenotypes**:
- Each gene pair also has 2 possible phenotypes (dominant and recessive).
- Therefore, the number of phenotypes is also \(2^n = 16\).

6. **Sum of Genotypes and Phenotypes**:
- The total number of possible combinations of genotypes and phenotypes in the F1 generation is:
- Total = Number of Genotypes + Number of Phenotypes = 16 + 16 = 32.

### Final Answer:
The sum of the genotype and phenotype possible in the F1 generation of the test cross is **32**.

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