Final answer:
Codominance is a type of genetic expression where two different alleles in a heterozygous genotype are fully expressed, resulting in a phenotype where both alleles are visible, as seen in the AB blood type in humans.
Step-by-step explanation:
When two different alleles of a heterozygous genotype are both fully expressed to produce the phenotype in a type of expression called codominance, each allele's effect is visible in the organism. An example of codominance is the ABO blood group system in humans, where both the A and B alleles are expressed equally in individuals with an AB blood type. Unlike incomplete dominance, where an intermediate phenotype is displayed, codominance results in a phenotype that fully shows both alleles.
The type of expression where two different alleles of a heterozygous genotype are both fully expressed to produce the phenotype is called codominance. In codominance, both alleles for the same characteristic are simultaneously expressed in the heterozygote. A classic example of codominance is the ABO blood groups in humans, where the A and B alleles are expressed equally in individuals with blood type AB.