Final answer:
The East Asian variant of aldehyde dehydrogenase acts in a codominant manner by simultaneously expressing the wild-type and mutant forms of the enzyme.
Step-by-step explanation:
The East Asian variant of aldehyde dehydrogenase acts in a codominant manner. Codominance is characterized by the equal, distinct, and simultaneous expression of both parents' different alleles. One example of codominance in humans is the ABO blood type system. Similar to how alleles for different enzymes produce different surface antigens on erythrocytes, the East Asian variant of aldehyde dehydrogenase exhibits codominance by simultaneously expressing the wild-type and mutant forms of the enzyme.