Inheritance and Variation — BIOLOGY STD 12 Science — Question

Incomplete dominance

Co-dominance

1. Incomplete dominance is seen when the phenotypes of the two parents blend together to create a new phenotype for their offspring.

1. Co-dominance is seen when the two parent phenotypes are expressed together in the offspring.

2. Both the genes of an allelomorphic pair express themselves partially in F₁ hybrids.

2. Both the genes of an allelomorphic pair express themselves equally in F₁ hybrids.

3. In incomplete dominance, a mixture of the alleles in the genotype is seen in the phenotype.

3. In co-dominance, both alleles in the genotype are seen in the phenotype.

4. The phenotypic effect of one allele is more prominent than the other.

4. The phenotypic effect of both the alleles is equally prominent.

5. Blending or intermixing of two alleles can be observed. A white flower and a red flower alleles mix and produce pink flowers.

Example : Pink flowers in Mirabilis jalapa.

5. No intermixing or blending effect of two alleles is observed. The colours don’t mix but are seen in patches.

Example : Roan colour in cattle.