Question

In pea plants, purple flowers (P) are dominant over white flowers (p) and tall stems (T) are dominant over short stems (t). Complete a dihybrid cross for parents with the genotypes: PpTT × ppTt and answer the following in complete sentences.
Describe how you would set up a Punnett square for this cross.
List the likelihood of each possible offspring genotype.
List the likelihood of each possible offspring phenotype.

Answer 1

This website should be a big help: http://www.biology.arizona.edu/mendelian_genetics/problem_sets/dihybrid_cross/03t.html

Basically you would form a punnett square with the genotype of one parent on one side and the other on the opposite side. From there you would count the number of each genotype/phenotype as a proportion of all of the genotypes/ phenotypes to find the likelihood or probability.