What is the ratio of phenotypes in the offspring of a monohybrid cross?

In a monohybrid cross, which involves a single trait determined by one gene with two alleles, the typical phenotypic ratio observed in the offspring is 3:1. This ratio arises when you cross two heterozygous parents (e.g., Aa x Aa), where "A" represents the dominant allele and "a" the recessive allele.

When you analyze the genotype combinations of the offspring, the possible genotypes are AA, Aa, Aa, and aa. Here, aa represents the homozygous recessive phenotype, while both AA and Aa represent the dominant phenotype. Thus, out of four possible combinations, three exhibit the dominant trait and one exhibits the recessive trait, leading to the ratio of 3:1 for the phenotypes.

This creates a clear distinction between the dominant and recessive traits, illustrating Mendel's principles of inheritance and providing a straightforward example of how traits can be passed down through generations.