Dihybrid Crosses & Independent Assortment
Ever wonder why you might have your mom's eyes but your dad's hair color? This is because of independent assortment! A dihybrid cross looks at how two different traits are inherited together.
Mendel tested this by crossing pea plants with round-yellow seeds (RRYY) with wrinkled-green seeds (rryy). He discovered something fascinating - the traits weren't linked together! The resulting F1 hybrids could produce four different types of gametes (RY, rY, Ry, ry) in equal amounts. When these F1 plants self-fertilized, the F2 generation showed a 9:3:3:1 phenotypic ratio of different seed types.
This led Mendel to formulate his law of independent assortment, which states that each pair of alleles segregates independently during gamete formation. So the inheritance of seed shape had no effect on the inheritance of seed color - they were completely independent!
Genetics in Action: You can see independent assortment in real life with Labrador retrievers, where coat color and other traits follow these same genetic patterns Mendel discovered in peas.
