dihybrid crosses

Dihybrid CrossesBy the end of today you should be able to:Use the Punnett sqaure method to solve basic dihybrid cross problems

• After crossing pea plants with one characteristic; Mendel wondered what would happen if more than one pair of characteristics were cross-fertilized.

• For example, what would happen if a round yellow pea was cross-fertilized with a wrinkled green pea?

• Mendel wanted to know if a gamete’s allele for the gene encoding pea colour would affect the allele for pea shape.

• Do you think one trait has an influence over another trait? Why or Why not?

•Mendel, created purebred round yellow peas, which can be represented by the genotype: RRYY

•He also created purebred wrinkled green peas, represented by the genotype: rryy

•He then cross fertilized these peas RRYY x rryy and recorded his observations.

•What do you think the phenotype of the F1 generation was? Why do you think this?

•All the resultant offspring were round yellow peas, with the genotype of RrYy.

•How do we know that?

Mendel’s 2nd Law

•The Law of Independent Assortment: when two or more pairs of characteristics are considered at one time, each pair shows dominance and segregation, independently of each other.

•http://163.16.28.248/bio/activelearner/10/ch10summary.html

•This website details dihybrid crosses quite nicely. It also has a quiz so you can check your understanding of dihybrid cross problems