A dihybrid cross tracks 2 genetic traits from 2 parents.
First you need to look at all the potential combinations of each parent
Parent 1: heterozygous tall & heterozygous round Tt & Rr
Parent 2: Homozygous dominant tall & wrinkled TT & rr
(use something like foil and look at all the possible options)
Parent 1: TR , tR, Tr, or tr
Parent 2: Tr
TR . tR . Tr tr
Tr . TT Rr . Tt Rr . TT rr Tt rr
Results show that 50% of offspring will be Tall & Round and 50% will be tall and wrinkled (phenotype)
however genotype displays a 1:1:1:1 ratio as none of the genotypes are exactly the same
Answer:
you dont have a picture of your question
The complete question is:
An individual with genotype AA is crossed to an individual with genotype aa at the same genetic locus. The allele A is dominant to the allele a.
If the offspring are interbred through two generations, what is the predicted ratio of phenotypes in the F2 generation?
9:16 (dominant:recessive)
9:7 (dominant:recessive)
3:16 (dominant:recessive)
1:3 (dominant:recessive)
Answer:
3:1 dominant:recessive phenotype ratios
Explanation:
The recessive phenotype disappears in the F1 generation, but it reappears in the F2 at a ratio of 3:1, being therefore dominant:recessive