Question

‘In incomplete dominance and co-dominance, genotypic and phenotypic ratios are identical.’ Explain how co-dominance differs from incomplete dominance in phenotypic nature of their hybrids.

Answer 1

i. Co-dominance is a condition in which both alleles of a gene pair in heterozygous condition are fully expressed, with neither one being dominant or recessive to the other.

Genotypic ratio of Co-dominance → 1:2:1

Phenotypic ratio of Co-dominance → 1:2:1

ii. Incomplete dominance can be defined as a phenomenon in which neither of the alleles of a gene is completely dominant over the other and hybrid is intermediate between the two parents.

Genotypic ratio of Incomplete dominance → 1:2:1

Phenotypic ratio of Incomplete dominance → 1:2:1

iii. In incomplete dominance, the phenotype of hybrid is intermediate between the phenotypes of parents, whereas in co-dominance, there is no intermediate expression as both the alleles express themselves independently.