Final answer:
The gene 'I' associated with the ABO blood-type system has three alleles: the dominant alleles IA and IB, as well as the recessive allele i. Each individual inherits two alleles that determine their blood type, with six possible genotypes existing in the population.
Step-by-step explanation:
The gene 'I' has three alleles, which include the dominant 'A' version, the dominant 'B' version, and the recessive 'i' version. An example of multiple alleles is the ABO blood-type system in humans. In this case, the IA allele codes for A molecules on red blood cells, the IB allele codes for B molecules, and the i allele codes for no molecules on the red blood cells. Both IA and IB alleles are dominant over the i allele. Each individual only inherits two alleles, which produce different genotypes and phenotypes.
The human ABO blood-type system is a classic example of multiple alleles in a population. The gene responsible for ABO blood typing has three alleles: IA, IB, and i. IA codes for the presence of A molecules on red blood cells, IB for B molecules, and the i allele does not produce any molecules on the red blood cells. The IA and IB alleles exhibit codominance where both alleles are expressed equally when present together, and they are both dominant over the i allele. As a result, individuals can have one of four blood types (A, B, AB, or O), which are determined by the combination of alleles they inherit from their parents. This inheritance results in six possible genotypes (IAIA, IAi, IBIB, IBi, IAIB, ii) for these three alleles at the population level, with only two alleles present in any individual.