Codominant alleles are present in __________.

• A. polygene inheritance
• B. sex-linked inheritance
• C. multiple-allele inheritance
• D. dominant-recessive inheritance

Answer: (C)

Verified step by step guidance

1. Understand the concept of codominant alleles: Codominance occurs when two different alleles at a locus are both fully expressed in a heterozygous individual, resulting in a phenotype that shows both traits equally.
2. Identify the types of inheritance patterns: The problem mentions polygene inheritance, sex-linked inheritance, multiple-allele inheritance, and dominant-recessive inheritance.
3. Review multiple-allele inheritance: This is a type of inheritance where more than two alleles exist for a particular gene, but an individual can only have two of these alleles. Codominance can occur in this context when two alleles are equally expressed.
4. Consider examples of codominance: A classic example is the ABO blood group system in humans, where both A and B alleles are codominant, resulting in the AB blood type.
5. Conclude that codominant alleles are present in multiple-allele inheritance, as this is the context where codominance is typically observed, allowing both alleles to be expressed equally in the phenotype.