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 x ppTt and answer the following in complete sentences. (5 points)

1. Describe how you would set up a Punnett square for this cross.

2. List the likelihood of each possible offspring genotype.

3. List the likelihood of each possible offspring phenotype.

Answer 1

I don't really remember how to do this since I did it a while ago, but I will give it a try. I got a 92 in biology.

Answer 2

First of all, nice grade!

I agree, and I'll clarify.
You have PpTT and ppTt.
Let's look at the significance of the letters first, using PpTT as an example. For reproduction, each parent donates a trait, like flower color. We have two flower colors, purple and white, and one letter to represent this. We use the letter P, which is chosen because it is the first letter of the dominant trait, so you can keep track of that. We use uppercase "P" for the dominant trait, which will show up when with a more recessive trait; and lowercase "p" for the recessive trait.
There are two copies of this trait - one from each parent. Because that's how reproduction works.
Pp means one parent gave a dominant color (purple) while the other gave a recessive color (white).

First, what will the PpTT parent donate? It will donate both traits, of course, or it's not a whole pea plant genome! But just one version of the trait can be donated. It, alone, will later combine with ppTt's versions. PpTT has a P or a p.

And a T.

Answer 3

Note that this is a table not to find offspring, but to find what will be donated.