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

1. The Punnett square would look like this
     |    PT    |    PT    |    pT    |    pT    |
pT | PpTT   |  PpTT  |  ppTT |   ppTT |
pt  | PpTT   |  PpTt   |  ppTt   |  ppTt   |
pT | PpTT   |  PpTT  |  ppTT |  ppTT  |
pt  | PpTt    |  PpTt    |  ppTt  |   ppTt  |

2. Looking at the results, there are:
PpTT - 5 [5/16 chance]
PpTt - 3 [3/16 chance]
ppTT - 4 [4/16 or 1/4 chance]
ppTt - 4 [4/16 or 1/4 change]

3. The possible phenotype are:
Purple and Tall - 8 [8/16 or 1/2 chance]
White and Tall - 8 [8/16 or 1/2 chance]
Purple and Short - 0 [0 chance]
White and Short - 0 [0 chance]