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.

In a monohybrid cross, starting with parents which are homozygous dominant and homozygous recessive, F₁ , at the same time with incomplete dominance can show identical genotypic and phenotypic ratios.

Sometimes F₁ had a phenotype that did not resembled either of the two parents and was in between them.The inheritance of flower colour in dog flower is a good example

In a cross between true breeding red flowered (RR) true breeding white flowered plants (rr), the F₁ was pink. When F₁ was self pollinated , the F₂ resulted in the following ratio 1 (RR) Red : 2 (Rr) Pink : 1 (rr) White. Here the genotype ratios were exactly as we would expect in any Mendelian monohybrid cross; but the phenotype ratio had changed from 3:1 dominant : recessive ratio. Here R was not completely dominant over r and this made it possible to distinguish Rr as pink from RR (red) and rr (white).

The genotypic and phenotypic ratios are the same as 1:2:1 in this example.