What is a trihybrid cross?
A trihybrid cross examines the inheritance of three different genes simultaneously. Each parent contributes one allele for each of three loci, producing gametes with 2³ = 8 possible combinations. When two trihybrid individuals are crossed, the resulting Punnett square has 8 × 8 = 64 cells.
The 27:9:9:9:3:3:3:1 ratio
The classic trihybrid cross (AaBbCc × AaBbCc) produces the following phenotypic ratio under complete dominance for all three loci:
- 27/64 display all three dominant traits
- 9/64 for each combination with one recessive pair
- 3/64 for each combination with two recessive pairs
- 1/64 display all three recessive traits
How to use this calculator
Select the genotypes for each of the three genes for both parents. The calculator will generate all 64 possible offspring and display the phenotypic ratios.