Enter two parent genotypes (six letters representing three gene pairs) to generate the complete 8×8 trihybrid Punnett square and phenotypic ratios.
A trihybrid cross involves three independently assorting genes. Each heterozygous parent (AaBbCc) produces 2³ = 8 different gamete types. The resulting 8×8 Punnett square shows 64 possible offspring zygotes. For a heterozygous × heterozygous cross, the classic phenotypic ratio is 27:9:9:9:3:3:3:1.
The 8×8 Punnett square is only valid when the three genes assort independently—either located on different chromosomes or far apart on the same chromosome so that recombination breaks any linkage.