Multitrait inheritance/Dihybrid crossing

What is dihybrid crossing

A cross using 2 traits

Why did mendel start dihybrid crossing

He wanted to know if the inheritance of 1 trait affected the inheritance of another trait

Like does pea shape affect pea colour

How did mendel test dihybrid crossing

1. He used 2 types of parental pea plants, yellow colour/round shape (Dom), and

   green colour/wrinkled shape (Rec)

2. He bred the parents to mix of the dominant and rececive traits (F1 gen=RrYy, RrYy, etc)

3. He then bred the F1 generation to see if there were any patterns in 1 trait appearing with another

4. There were not any patterns

What is the law of independent assortment

The inheritance of an allele for one trait does not affect the inheritance of another allele from a different trait

What is the product law

The probability of 2 or more outcomes happening is the same as multiplying the probabilty of the individual outcomes.

E.g. chance of having 2 boy in a row. The chance of having a boy is 50% or 1/2 so when you multiply 1/2 by 1/2 you get 1/4 . So the chance of having 2 boys in a row is 25%.

Similar to punnett squares.