Punnett Square Maker

A Punnett square is a grid diagram in genetics that predicts the possible genotype combinations of offspring from a cross between two parents. Each parent's alleles label the rows and columns, and each cell in the grid contains one possible offspring genotype. The frequency of each genotype in the grid gives the expected probability of that genotype among offspring.

A monohybrid Punnett square tracks one gene with two alleles. Write one parent's two alleles along the top row and the other parent's two alleles down the left column. Fill each cell with one allele from the column and one from the row. The result is a 2×2 grid showing four possible genotypes. For a cross of two heterozygotes (Aa × Aa) the ratio is 1 AA : 2 Aa : 1 aa. SciFig's Punnett square maker fills and labels this grid automatically.

A dihybrid Punnett square tracks two genes simultaneously and produces a 4×4 grid with 16 cells. Use the FOIL method to list the four possible gametes for each parent (for AaBb parents: AB, Ab, aB, ab) as the column and row headers. Fill each cell with the corresponding gamete combination. The classic dihybrid ratio is 9:3:3:1 for phenotypes when both genes show complete dominance. SciFig's Punnett square maker generates the full 4×4 grid with all 16 genotypes correctly filled.

A giant Punnett square (also called a large or expanded Punnett square) is used for trihybrid or higher-order crosses involving three or more gene loci. For a trihybrid cross (AaBbCc × AaBbCc) the grid is 8×8 with 64 cells covering all possible gamete combinations. Giant Punnett square makers are used in advanced genetics courses to visualize multi-trait inheritance probabilities that would be tedious to calculate by hand.

Count the frequency of each unique genotype in the grid cells — that frequency divided by total cells gives the probability. For phenotype ratios, group genotypes by whether they express the dominant or recessive phenotype (for complete dominance, any genotype with at least one dominant allele expresses the dominant phenotype). SciFig's Punnett square maker labels genotype ratios and phenotype ratios alongside every grid it generates.

Yes. For incomplete dominance, the heterozygous genotype produces an intermediate phenotype (for example, red × white = pink in snapdragons). For codominance, both alleles are expressed simultaneously (for example, blood type AB). Specify the inheritance pattern in your prompt and SciFig's Punnett square maker labels phenotypes correctly for each genotype cell in the grid.