Consider the cross shown. In this cross, a wrinkled pea is crossed with a round pea.

Question

Which allele is dominant?

Which allele is recessive?

Answer 1

In pea plants, the allele for round peas (R) is dominant, while the allele for wrinkled peas (r) is recessive. Therefore:

• Dominant allele: Round pea (R)
• Recessive allele: Wrinkled pea (r)

When a wrinkled pea (rr) is crossed with a round pea (RR or Rr, depending on the genotype of the round pea), the offspring will display the dominant phenotype (round peas) if at least one round allele (R) is present.