Two pink-flowered snapdragons (incomplete dominance) are crossed. What is the expected phenotypic ratio of their offspring?
Answer and explanation
Correct answer: B. 1 red : 2 pink : 1 white
- Step 1: Rr × Rr gives RR, Rr, Rr and rr, and each genotype has its own flower colour.
Answer
1 red : 2 pink : 1 white.
Why not the others: 3 red : 1 white: this ratio applies when one allele is completely dominant. All pink: pink plants are heterozygous and produce both kinds of gamete. 1 pink : 1 white: red offspring are also produced, since each parent passes on R half the time.
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