Question

You perform a cross between two pea plants that have the following genotypes: PP Yy Tt and Pp Yy tt. The alleles code for flower color (PP, Pp= purple flowers pp= white flowers) seed color (YY,Yy= yellow seeds, yy= green seeds) and plant height (TT,Tt= tall plant, tt= short plant). What percentage of the offspring will have the genotype Pp YY Tt?

Answer 1

Using a Punnett square, you can calculate the percentage of offspring with the genotype Pp YY Tt as 6.25% from the cross between PP Yy Tt and Pp Yy tt.

Step-by-step explanation:

Calculating the Offspring Genotype from a Dihybrid Cross

To determine the percentage of offspring with the genotype Pp YY Tt from the cross PP Yy Tt (purple flowers, yellow seeds, tall plant) and Pp Yy tt (purple flowers, yellow seeds, short plant), we need to use the Punnett square.

For the flower color (P), the cross PP x Pp gives us offspring genotypes of PP or Pp, as the white flower allele (p) is not present in the first parent. For the seed color (Y), the cross Yy x Yy gives YY, Yy, or yy.

Lastly, the plant height (T) cross Tt x tt gives Tt or tt.

Combining these individual punnett squares, the likelihood of getting a Pp genotype is 1/2, the YY genotype is 1/4, and the Tt genotype is 1/2.

Therefore, the percentage of offspring with the genotype Pp YY Tt is 1/2 (for Pp) * 1/4 (for YY) * 1/2 (for Tt), which equals 1/16 or 6.25%.