A gene showing codominance has

Options

A. Alleles that are recessive to each other
B. Both alleles independently expressed in the heterozygote
C. One allele dominant on the other
D. Alleles tightly linked on the same chromosome

Answer

### Step-by-Step Solution:

1. **Understanding Codominance**:
- Codominance occurs when both alleles in a heterozygote are fully expressed, resulting in a phenotype that is neither dominant nor recessive. This means that both traits are visible in the organism.

2. **Analyzing the Options**:
- **Option 1**: "Alleles that are recessive to each other."
- This is incorrect because codominance involves alleles that are not recessive to each other; instead, they are both expressed.

- **Option 2**: "Both alleles independently expressed in the heterozygote."
- This is correct. In codominance, both alleles contribute to the phenotype in a way that both traits can be observed simultaneously.

- **Option 3**: "One allele dominant on the other."
- This describes complete dominance, not codominance. In codominance, no allele is dominant over the other.

- **Option 4**: "Alleles tightly linked on the same chromosome."
- This refers to genetic linkage, which is unrelated to the concept of codominance.

3. **Conclusion**:
- The correct answer is **Option 2**: "Both alleles independently expressed in the heterozygote."