Final answer:
The alleles responsible for the ABO blood types of humans are an example of multiple alleles and codominance. The ABO blood type system is determined by three alleles: IA, IB, and i. Both the IA and IB alleles are codominant with each other, and both are dominant over the i allele.
Step-by-step explanation:
The alleles responsible for the ABO blood types of humans are an example of multiple alleles and codominance.
The ABO blood type is determined by three alleles: IA, IB, and i. The IA allele codes for the A blood group antigen, the IB allele codes for the B blood group antigen, and the i allele codes for no antigen. Both the IA and IB alleles are codominant with each other, meaning that if an individual has both IA and IB alleles, they will have AB blood type where both antigens are expressed equally. These alleles are also both dominant over the i allele, which codes for O blood type.
Therefore, the ABO blood type system is an example of multiple alleles and codominance.