Question

In a Mendelian monohybrid cross, the F2 generation shows identical genotypic and phenotypic ratios. What does it tell us about the nature of alleles involved? Justify your answer.

Answer 1

In a monohybrid cross, starting with parents which homozygous dominant and homozygous recessive, F1 , would be heterozygous for the trait and would express the dominant allele. But in case of incomplete dominance, a monohybrid cross shows the result as follows.

Phenotypic ratio —> Red : Pink :White :: 1 : 2 : 1

Genotypic ratio —> RR : Rr: rr : .1:2:1

Here the genotypic and phenotypic ratios are the same. So, we can conclude that when genotypic and phenotypic ratios are the same, the alleles show incomplete dominance.