In Mendelian genetics, what is the expected phenotypic ratio in the F2 generation of a classic dihybrid cross involving two independent traits, such as seed shape and seed color in pea plants?

💡 Solution & Explanation

A dihybrid cross tracking two unlinked traits yields an F2 phenotypic ratio of 9 to 3 to 3 to 1, reflecting independent assortment of allele pairs during gamete formation as established by Gregor Mendel. A monohybrid cross produces a phenotypic ratio of 3 to 1 and a genotypic ratio of 1 to 2 to 1. Gene interactions such as recessive epistasis can modify these standard Mendelian ratios. Chromosomal theory of inheritance linked Mendelian factors to physical chromosomes.