Final answer:
Incomplete dominance occurs when a heterozygote has a phenotype that is intermediate between dominant and recessive phenotypes, with snapdragons being a classic example.
Step-by-step explanation:
When a heterozygote is a phenotypic intermediary between the dominant and recessive phenotypes, this situation is an example of incomplete dominance. In incomplete dominance, the pattern of inheritance is such that the heterozygous genotype expresses a phenotype that is intermediate between the dominant and recessive phenotypes. A classic illustration of this concept occurs in snapdragons, where crossing a red-flowered plant with a white-flowered plant results in offspring with pink flowers (CRCW). In incomplete dominance, we often see a 1:2:1 phenotypic ratio, which provides insights into an organism's genotype directly from its phenotype without needing extensive breeding tests.
Learn more about Incomplete Dominance