Dihybrid Cross Calculator
Calculate genotype and phenotype probabilities for two genetic traits using Punnett squares
🧬 Parental Genotypes
Parent 1
Parent 2
📚 Dihybrid Cross Concepts
(3:1) × (3:1) = 9:3:3:1 Phenotype Ratio
Classic dihybrid cross ratio for two heterozygous traits
Key Principles:
- • Law of Independent Assortment: Genes for different traits segregate independently
- • Gamete Formation: Each parent produces 4 types of gametes
- • Punnett Square: 4×4 grid showing 16 possible offspring combinations
- • Phenotype Ratio: 9:3:3:1 for two heterozygous traits
🔍 Dihybrid Punnett Square
Total Possible Genotypes
16
Unique Genotypes
9
Dominant for Both
56.25%
Recessive for Both
6.25%
📊 Phenotype Probabilities
🧬 What is a Dihybrid Cross?
A dihybrid cross examines the inheritance of two different traits simultaneously. It demonstrates Mendel’s Law of Independent Assortment.
In a classic dihybrid cross between heterozygous parents (RrYy × RrYy), the offspring show a 9:3:3:1 phenotype ratio.
Gametes: RY, Ry, rY, ry (for RrYy)
Each heterozygous parent produces 4 gamete types
⚖️ Mendelian Ratios
Dihybrid crosses reveal predictable inheritance patterns:
- ✓ 9/16: Dominant for both traits
- ✓ 3/16: Dominant A, Recessive B
- ✓ 3/16: Recessive A, Dominant B
- ✓ 1/16: Recessive for both traits
(3:1)ⁿ for n traits
General formula for multiple trait inheritance
🔍 Applications in Genetics
Dihybrid crosses are essential for:
- • Understanding gene linkage and recombination
- • Plant and animal breeding programs
- • Genetic counseling for multiple traits
- • Evolutionary biology studies
- • Forensic genetics
Note: This calculator assumes independent assortment. Linked genes on the same chromosome may show different ratios.