Question

Explain inheritance by multiple alleles.

Answer 1

Inheritance by multiple alleles refers to the occurrence of more than two allelic forms of a gene in a population, all of which occupy the same locus on homologous chromosomes. These multiple alleles include one dominant and one recessive allele, while others may have intermediate dominance. A classic example is the human ABO blood group system, determined by three alleles: (I^A), (I^B), and (i). Here, (I^A) and (I^B) are co-dominant, and both dominate over (i). This results in various genotypes producing four blood groups (A, B, AB, and O), illustrating inheritance by multiple alleles with codominance and dominance interactions.