How do "Pleiotropy", 'incomplete dominance", "co-dominance" and "polygenic inheritance" deviate from the observation made by Mendel ? Explain with the help of one example for each.

Explanation

To address the question of how "Pleiotropy," "Incomplete Dominance," "Co-dominance," and "Polygenic Inheritance" deviate from Mendel's observations, we can break down each concept and provide an example for clarity.

### Step-by-Step Text Solution:

1. **Pleiotropy**:
- **Definition**: Pleiotropy occurs when a single gene influences multiple phenotypic traits.
- **Deviation from Mendel**: Mendel's laws suggest that one gene controls one trait. However, in pleiotropy, one gene can affect several traits simultaneously.
- **Example**: Sickle cell anemia is caused by a single defective gene that alters hemoglobin production. This gene not only leads to the characteristic sickle-shaped red blood cells but also provides resistance to malaria. Thus, one gene is responsible for multiple traits.
...