1. Codominance: In codominance, both alleles for a trait are expressed equally in the phenotype. A classic example is the ABO blood group system. Individuals with the AB blood type inherit both the A and B alleles, and both are expressed, leading to the production of both A and B antigens on red blood cells.

2. Incomplete Dominance: In incomplete dominance, neither allele completely masks the other. The heterozygous phenotype is a blend or intermediate between the two homozygous phenotypes. A common example is the snapdragon flower. A red homozygous flower crossed with a white homozygous flower will produce pink heterozygous offspring.