Question

which statement describes codominant alleles?
○ two alleles that blend to create an intermediate phenotype
○ two alleles that are expressed separately and equally
○ any allele that can hide the presence of a different allele
○ any allele whose presence can be masked by another allele

Explanation:

Codominance is a genetic concept. In codominance, both alleles in a heterozygote are expressed simultaneously without blending. For example, in the ABO blood - group system, the \(I^A\) and \(I^B\) alleles are codominant. A person with genotype \(I^AI^B\) has blood type AB, where both \(A\) and \(B\) antigens are expressed separately and equally on the red blood cells.

• Option A describes incomplete dominance (where alleles blend to create an intermediate phenotype).
• Option C describes a dominant allele (an allele that can hide the presence of a different allele).
• Option D describes a recessive allele (an allele whose presence can be masked by another allele).

Answer:

B. two alleles that are expressed separately and equally