Understanding Mendel's Genetic Experiments
Gregor Mendel, the father of genetics, used pea plants to figure out how traits are inherited. In his famous experiments, he crossed purple flowers (homozygous dominant, PP) with white flowers (homozygous recessive, pp).
The first generation (F₁) all had purple flowers despite having mixed genetics (Pp). This showed that the dominant trait masks the recessive one. When these F₁ plants bred together, the second generation (F₂) showed a pattern: about 75% had purple flowers and 25% had white.
Mendel's simple crosses worked well for single traits, but he discovered that some traits don't follow these simple rules. Some genes are linked, meaning they're inherited together rather than independently.
Remember This: The 3:1 ratio (75% dominant to 25% recessive) in the F₂ generation is a classic sign that you're dealing with a simple dominant/recessive inheritance pattern!
For studying two traits at once, scientists use a dihybrid cross. This more complex Punnett square tracks two different gene pairs simultaneously, giving us insight into how multiple traits are inherited together.