Question

why are the genotype and phenotype ratios one and the same

Answer 1

Codominance is a condition in which there is no dominant allele, and in the heterozygote both alleles will be completely expressed. Hence, the phenotype is different for heterozygotes as both the traits are expressed distinctly in the same individual.


Incomplete dominance is a condition in which both the alleles of a heterozygote are expressed partially resulting in an intermediate phenotype. Therefore, here also the phenotype is different for heterozygotes.

Since, in both the conditions heterozygous phenotype is different, the phenotypic ratio and the genotypic ratio are same for both the cases. So, we cannot say that if the phenotypic and genotypic ratio are same then it is incomplete dominance, it can also be co dominance.