A student crosses two pea plants. One is homozygous dominant for axial flowers, and the other is heterozygous for axial flowers. If the student examines 200 offspring pea plants, which of the following is a reasonable result?
A.
200 with axial flowers, 0 with terminal flowers
B.
149 with axial flowers, 51 with terminal flowers
C.
98 with axial flowers, 102 with terminal flowers
D.
47 with axial flowers, 153 with terminal flowers
The student is crossing a homozygous dominant plant (AA) and a heterozygous plant (Aa). Crossing these two plants will result in offspring with the genotype combinations of AA and Aa.
Since the axial flower trait is dominant (A), all offspring with the genotype AA or Aa will exhibit axial flowers. Only offspring with the genotype aa will exhibit terminal flowers.
When crossing a homozygous dominant plant (AA) with a heterozygous plant (Aa), there is a 50% chance of each genotype in the offspring.
Therefore, out of the 200 offspring examined:
- 50% (100 offspring) would be expected to have the genotype AA and exhibit axial flowers
- 50% (100 offspring) would be expected to have the genotype Aa and exhibit axial flowers
So, option C is the most reasonable result:
98 with axial flowers, 102 with terminal flowers