Two parents having two loci incompletely linked and heterozygous in nature are crossed. What would be the distribution of phenotypic feature in the `F_2` generation ?

Options

A. Only parental phenotype
B. Only recombinant phenotype
C. High parental and low recombinant phenotype
D. Low parental and high recombinant phenotype

Answer

To solve the problem of determining the distribution of phenotypic features in the F2 generation from a cross between two heterozygous parents with incompletely linked loci, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Parental Genotypes**:
- Let's denote the alleles at the two loci as A/a and B/b. The parental genotypes can be represented as AABB (homozygous dominant) and aabb (homozygous recessive).

2. **Cross the Parents**:
- When we cross AABB with aabb, all F1 offspring will be heterozygous (AaBb).

3. **Determine the Gametes from F1**:
- Since the loci are incompletely linked, we can expect some recombination. The possible gametes produced by the F1 generation (AaBb) will include:
- Parental gametes: AB and ab
- Recombinant gametes: Ab and aB

4. **Gamete Frequency**:
- In incompletely linked genes, the frequency of recombinant gametes is less than 50%. For example, if we assume a recombination frequency of 20%, the gamete distribution could be:
- AB: 40%
- ab: 40%
- Ab: 10%
- aB: 10%

5. **F2 Generation Formation**:
- The F2 generation is formed by self-crossing the F1 (AaBb) individuals. The expected phenotypic ratio can be derived from the gametes:
- Parental phenotypes (AB and ab) will be more frequent.
- Recombinant phenotypes (Ab and aB) will be less frequent.

6. **Phenotypic Ratio Calculation**:
- If we consider a total of 100 offspring, we might expect:
- Parental phenotypes: 80 (40 AB + 40 ab)
- Recombinant phenotypes: 20 (10 Ab + 10 aB)

7. **Conclusion**:
- The F2 generation will show a distribution of phenotypes where the parental types are more frequent than the recombinant types. Therefore, we can conclude that there will be a high parental phenotype and a low recombinant phenotype.

### Final Answer:
The distribution of phenotypic features in the F2 generation will show a high frequency of parental phenotypes and a low frequency of recombinant phenotypes.