Final answer:
Incomplete dominance occurs when the phenotype of a heterozygote offspring is somewhere in between the phenotypes of both homozygous parents. When you mate a red plant with a white plant, the offspring will have pink flowers.
Step-by-step explanation:
Incomplete dominance occurs when the phenotype of a heterozygote offspring is somewhere in between the phenotypes of both homozygous parents; a completely dominant allele does not occur. For example, when red snapdragons (CRCR) are crossed with white snapdragons (CWCW), the F₁ hybrids are all pink heterozygotes for flower color (CRCW). The pink color is an intermediate between the two parent colors. When two F₁ (CRCW) hybrids are crossed they will produce red, pink, and white flowers. The genotype of an organism with incomplete dominance can be mined from its phenotype.
In the case of incomplete dominance, when a red plant RR is crossed with a white plant R'R', the resulting offspring will exhibit a phenotype that is intermediate between the two parent's traits. Specifically, the offspring will have pink flowers with the genotype RR'. In contrast, when discussing co-dominance and a red plant RR is mated with a white plant WW, if R and W are co-dominant alleles, the resulting offspring will exhibit a phenotype where both red and white traits are equally expressed. The progenies will possess a genotype that is not blended but instead shows RW, meaning each flower might display both red and white patches or spots.
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