Which of the following is an example of codominance?

Which of the following is an example of codominance?

• A. ABO blood group system
• B. Height as a continuous trait
• C. Color of flowers showing a blend of red and white
• D. Only one allele being expressed in offspring

Answer: (A)

The ABO blood group system is an excellent example of codominance. In this genetic system, individuals inherit one allele from each parent, and when both alleles are present, they can express themselves simultaneously without one being dominant over the other. For instance, if a person inherits an A allele from one parent and a B allele from the other, they will have blood type AB, where both A and B antigens are expressed on the surface of red blood cells. This is a clear illustration of codominance, as both alleles contribute equally to the phenotype. In contrast, the continuous trait of height represents polygenic inheritance, where multiple genes contribute to a single phenotype. The blending of flower colors can be an example of incomplete dominance, where the phenotype is a mix of the two parental traits, rather than both being expressed distinctly. The idea of only one allele being expressed in offspring relates to complete dominance, where one allele overshadows the expression of another, which does not align with the concept of codominance.

The ABO blood group system is an excellent example of codominance. In this genetic system, individuals inherit one allele from each parent, and when both alleles are present, they can express themselves simultaneously without one being dominant over the other. For instance, if a person inherits an A allele from one parent and a B allele from the other, they will have blood type AB, where both A and B antigens are expressed on the surface of red blood cells. This is a clear illustration of codominance, as both alleles contribute equally to the phenotype.

In contrast, the continuous trait of height represents polygenic inheritance, where multiple genes contribute to a single phenotype. The blending of flower colors can be an example of incomplete dominance, where the phenotype is a mix of the two parental traits, rather than both being expressed distinctly. The idea of only one allele being expressed in offspring relates to complete dominance, where one allele overshadows the expression of another, which does not align with the concept of codominance.