Keystone Biology Practice Exam

The term that describes a pattern of inheritance where offspring exhibit a blended phenotype is known as incomplete dominance. Incomplete dominance occurs when the phenotype of heterozygous individuals is intermediate between the phenotypes of the two homozygous parents. This means that neither allele completely masks the other, resulting in a combination or blend of traits. For example, if one parent has red flowers and the other has white flowers, the offspring may have pink flowers, illustrating this blending effect.

In contrast, codominance, while it also involves two different alleles, results in both traits being fully expressed in the phenotype, rather than blended. Dihybrid inheritance refers to the inheritance involving two different traits, typically analyzed in terms of two gene pairs, while polygenic inheritance involves multiple genes contributing to a single trait, leading to a range of phenotypes, rather than a blended appearance. Thus, incomplete dominance specifically captures the essence of a blended phenotype in offspring.