1. Which is the correct set up for a dihybrid cross of two heterozygous parents Rr Yy x Rr Yy ? See following slides:. A. B. C. The correct set up for a heterozygous dihybrid cross is. A B C.
Dominant for both : Dom 1st/Rec. 2nd : Rec for 1st/Dom. for 2nd: Recessive for both
9 : 3 : 3 : 1
A dihybridPunnett square assumes that all 4 gamete combinations are equally likely.
This will occur if the two genes are on different chromosomes. Independent assortment will make all 4 combinations equally likely.
When two genes are on the same chromosome, genetic recombination can occur due to crossing over.
However, if the two genes are close together on the chromosome, the recombinants will not be equally like as the original combination.
Don’t need to fill out additional rows.
All gametes of gghh will be gh.
Ratio of 1:1: 1:1
25% chance dominant phenotype for both traits
25% chance dominant for G, recessive for h
25% chance recessive for g, dominant for H
25% chance recessive for both