Describe the inheritance of two genes.

(N/A) Mendel studied the inheritance of two genes by crossing pea plants that differed in two traits,such as seed color (yellow vs. green) and seed shape (round vs. wrinkled).
He crossed a plant with yellow,round seeds $(RRYY)$ with a plant having green,wrinkled seeds $(rryy)$.
The $F_{1}$ generation plants were all yellow and round $(RrYy)$,indicating that yellow color is dominant over green and round shape is dominant over wrinkled.
When Mendel self-pollinated the $F_{1}$ plants,the $F_{2}$ generation showed four types of phenotypes in a $9:3:3:1$ ratio: yellow-round,yellow-wrinkled,green-round,and green-wrinkled.
This experiment demonstrated the Law of Independent Assortment,which states that the segregation of one pair of traits is independent of the other pair of traits during gamete formation.