Which of the following is exception of Mendel's laws ?

Options

A. Linkage
B. Incomplete dominance
C. Co-dominance
D. All of the above

Answer

To determine which of the following is an exception to Mendel's laws, we need to analyze the options provided and identify the one that contradicts Mendel's principles of inheritance.

**Step 1: Understand Mendel's Laws of Inheritance**
Mendel's laws include:
- **Law of Dominance**: In a heterozygote, one allele may mask the expression of another.
- **Law of Segregation**: Alleles segregate independently during gamete formation.
- **Law of Independent Assortment**: Genes for different traits assort independently of one another.

**Step 2: Identify Exceptions to Mendel's Laws**
We need to look for phenomena that contradict these laws:
- **Linkage**: This occurs when two genes are located close to each other on the same chromosome, leading to a failure of independent assortment.
- **Incomplete Dominance**: In this case, the dominant allele does not completely mask the recessive allele, resulting in an intermediate phenotype.
- **Co-dominance**: Both alleles are expressed equally in the phenotype, which contradicts the idea of dominance.

**Step 3: Analyze the Options**
We need to check if the options provided include:
- Linkage
- Incomplete Dominance
- Co-dominance

If all these options are present, they all represent exceptions to Mendel's laws.

**Step 4: Conclusion**
Based on the analysis, if all the mentioned exceptions (linkage, incomplete dominance, and co-dominance) are included in the options, then the correct answer is **Option D: All of the above**.