Mendel’s monohybrid cross’s phenotypic ratio is 3 : 1. A monohybrid cross happens when fertilisation occurs between two true-breeding parents who differ exclusively in the feature being examined and the resulting offspring are termed monohybrids. Mendel experimented with seven different forms of monohybrid crosses, each including opposing features for various phenotypes. The F1 offspring of such crosses all had one parent’s phenotype, but the F2 offspring had a 3 : 1 phenotypic ratio. Mendel hypothesised that each parent in a monohybrid cross provided one amongst two paired unit factors towards each offspring and that any potential combination of unit factors seemed equally probable.
