Mendel's law of independent assortment holds good for genes situated on the

Options

A. non-homolgous chmologous
B. homologous chromosomes
C. extra nnclear genetic element
D. same chromosome

Explanation

### Step-by-Step Text Solution:

1. **Understanding Mendel's Law of Independent Assortment**:
- Mendel's law of independent assortment states that the alleles of different genes segregate independently of one another during the formation of gametes. This means that the inheritance of one trait will not affect the inheritance of another trait.

2. **Dihybrid Cross Experiment**:
- Mendel conducted a dihybrid cross using two traits: seed shape (round vs. wrinkled) and seed color (yellow vs. green). The parental generation consisted of pure plants for each trait. The F1 generation exhibited the dominant traits (round and yellow).

3. **F2 Generation and Ratios**:
- When the F1 generation was self-pollinated, the F2 generation exhibited a phenotypic ratio of 9:3:3:1. This ratio indicates that the traits assort independently, leading to combinations of traits that are not found in the parental generation.

4. **Linkage as an Exception**:
- However, Mendel's law of independent assortment does not apply when genes are located on the same chromosome. This phenomenon is known as linkage, where certain genes are inherited together due to their physical proximity on the chromosome.

5. **Conclusion**:
- Therefore, Mendel's law of independent assortment holds true for genes that are located on different chromosomes (non-homologous chromosomes). If genes are on the same chromosome (homologous chromosomes), they will show linkage and not assort independently.

### Final Answer:
Mendel's law of independent assortment holds good for genes situated on **different chromosomes** (non-homologous chromosomes).

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