Dihybrid Cross Calculator

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Parent Genotypes

Parent 1

Parent 2

Use uppercase for dominant and lowercase for recessive (e.g., AaBb).

Punnett Square

Invalid genotype format

Phenotype Ratios

About Dihybrid Crosses

A dihybrid cross tracks the inheritance of two different traits (e.g. seed color and shape). The standard Mendelian F2 ratio for a cross between two double-heterozygotes (AaBb × AaBb) is 9:3:3:1.

Gregor Mendel is known as the 'Father of Modern Genetics' for his work with pea plants (1856-1863).
The 9:3:3:1 ratio assumes independent assortment of the two genes.
This ratio means: 9 dominant for both, 3 dom/rec, 3 rec/dom, and 1 recessive for both.
Deviations from this ratio can suggest gene linkage (genes on the same chromosome).