Question

Sol.(a) [Key Concept: Codominance — Both Alleles Expressed] When both dominant and recessive alleles express themselves simultaneously (both are fully expressed in the heterozygote), the phenomenon is called codominance. The classic example is ABO blood group (I^A I^B genotype shows both A and B antigens — blood group AB). In true dominance, only one allele is expressed. Incomplete dominance produces an intermediate phenotype.