Imagine you do a test cross between a purple-flowered pea plant having serrated leaves (a dominant trait)and a white-flowered pea plant having smooth edges. If the purple-flowered plant is heterozygous for both traits, the expected ratio in the offspring is 1 purple-serrated:1 purple-smooth:1 white-serrated:1 white-smooth. Instead, you see 4 purple-serrated:1 purple-smooth:1 white-serrated:4 white-smooth. What is the explanation of this ratio?

Question

Quizplus · Accepted Answer

The observed ratio suggests that the genes for flower color and leaf edge are linked on the same chromosome, which resulted in more frequent occurrence of parental combinations (purple-serrated and white-smooth) and less frequent occurrence of recombinant combinations (purple-smooth and white-serrated) in the offspring. There is no evidence of incomplete dominance or mutation in this scenario.

Imagine You Do a Test Cross Between a Purple-Flowered Pea