Kaplan Nursing Entrance Exam Practice 2025 – Comprehensive Prep

Codominance is characterized by the full expression of both traits in a heterozygous individual. In this genetic scenario, neither allele is dominant or recessive; instead, both contribute to the phenotype. A classic example of codominance is seen in certain blood types. For instance, individuals with the AB blood type express both A and B antigens on the surface of their red blood cells, demonstrating that both alleles are fully and equally represented in the organism's physical traits.

The other characteristics listed do not apply to codominance. The idea that one trait is dominant over another reflects the principle of complete dominance. Blending of traits refers to incomplete dominance, where a mixed phenotype appears, such as a pink flower resulting from the mixing of red and white flower traits. Lastly, independent trait expression relates to the law of independent assortment, describing how different genes independently separate from one another when reproductive cells develop. In codominance, traits do not act independently but instead are both distinctly expressed.