Mendel and Hardy-Weinberg

Mendel's Three-to-One Ratio

Dominant and recessive phenotypes aggregate the monohybrid genotypes.

highlighted = computed this step

Dominant genotypes share one phenotype

AA and Aa both show the dominant phenotype, while aa shows the recessive phenotype. Phenotype ratios aggregate genotypes that look the same.

phenotype=classify⁡(genotype)\text{phenotype}=\operatorname{classify}(\text{genotype})
Genotype to phenotypeEach genotype is classified by dominance.GenotypePhenotypeAAdominantAadominantaarecessive

Mendel's phenotype ratio is three to one

For Aa crossed with Aa, the phenotype ratio is 3:1: dominant to recessive.

3:13:1
Phenotype ratioPhenotype probabilities are aggregated from genotype probabilities.PhenotypeProbabilityRatiodominant3/43recessive1/41