ILTS Elementary Education Grades 1–6 (305) Practice Exam

The term incomplete dominance refers to a genetic situation where two different alleles contribute to a trait, resulting in a phenotype that is a blending of both parental traits. Instead of one allele completely overshadowing the other, as seen in complete dominance, incomplete dominance leads to a middle ground in the expression of the trait.

For example, if one parent has red flowers (RR genotype) and the other has white flowers (rr genotype), the offspring may exhibit pink flowers (Rr genotype), demonstrating the blending of the red and white traits. This illustrates how incomplete dominance allows for an intermediate phenotype to emerge, showcasing the contributions of both alleles rather than one fully dominating the other.

The other options describe different concepts in genetics: complete dominance refers to one allele overpowering another, unexpressed genes pertain to recessive traits that do not manifest, and complete erasure of dominant traits does not align with the principles of genetic inheritance. Therefore, the correct interpretation of incomplete dominance is centered on the blending of traits, which is aptly captured by the idea of traits blending together from two parents.