Criss-cross inheritance is a type of inheritance pattern that occurs when two traits are inherited from a common ancestor, but not directly from the parents. In this pattern, the inheritance of traits crisscrosses over generations, leading to a unique pattern of inheritance.

Explanation:

Definition:
Criss-cross inheritance refers to the phenomenon in genetics where two traits are inherited from a common ancestor, but they are not directly inherited from the parents. Instead, the traits crisscross over generations, creating a unique inheritance pattern.

Example:
To understand criss-cross inheritance, let's consider an example with two traits - Trait A and Trait B. Suppose we have a male individual with Trait A and a female individual with Trait B. In a typical inheritance pattern, we would expect their offspring to inherit Trait A from the male and Trait B from the female. However, in criss-cross inheritance, the opposite occurs.

With criss-cross inheritance, the male offspring will inherit Trait B from the mother and pass it on to their daughters. On the other hand, the female offspring will inherit Trait A from the father and pass it on to their sons. This crisscrossing of traits between generations creates a unique pattern of inheritance.

Key Points:
- Criss-cross inheritance occurs when two traits are inherited from a common ancestor but not directly from the parents.
- The inheritance pattern crisscrosses over generations, leading to a unique pattern of inheritance.
- In criss-cross inheritance, males inherit one trait from the mother and pass it on to their daughters, while females inherit the other trait from the father and pass it on to their sons.
- This pattern can be observed in various genetic traits, including those controlled by sex-linked genes.

Conclusion:
Criss-cross inheritance is an interesting inheritance pattern where two traits are inherited from a common ancestor, but not directly from the parents. The crisscrossing of traits between generations creates a unique pattern of inheritance. Understanding this pattern helps in studying the inheritance of various genetic traits and their transmission across generations.