25
%
50
%
25
%
75
%
25
%
25
%
50
%
25
%
75
%
25
%
The Monohybrid Cross Calculator predicts offspring genotype and phenotype ratios from a single-gene cross between two parents. This is the most fundamental type of genetic cross, first described by Gregor Mendel. It illustrates the principles of dominance, segregation, and independent assortment for one trait.
Enter each parent's genotype as the number of dominant alleles (2=AA, 1=Aa, 0=aa), and the calculator will produce the expected offspring ratios.
A monohybrid cross considers one gene with two alleles. Each parent passes one allele to offspring. A Punnett square shows all possible combinations:
For Aa × Aa: offspring are 25% AA, 50% Aa, 25% aa (genotype ratio 1:2:1). The phenotype ratio is 3 dominant : 1 recessive (75%:25%).
For Aa × aa: offspring are 50% Aa, 50% aa (phenotype ratio 1:1).
For AA × aa: all offspring are Aa (100% dominant phenotype).
Inputs
Results
The classic 3:1 phenotype ratio. 25% AA, 50% Aa, 25% aa. Three-quarters show the dominant trait, one-quarter the recessive.
Inputs
Results
All offspring are heterozygous (Aa), showing the dominant phenotype. This is the F1 generation of a classic Mendelian cross.
A monohybrid cross is a genetic cross between two organisms that differ in a single trait controlled by one gene with two alleles. "Mono" means one, and "hybrid" refers to offspring from genetically different parents. It was first systematically studied by Mendel using pea plants with traits like seed color and plant height.
When two heterozygotes (Aa) cross, each parent can pass either A or a with equal probability (50%). The Punnett square shows 4 equally likely outcomes: AA, Aa, aA, aa. Three of four carry at least one dominant allele (showing the dominant phenotype), while only one is homozygous recessive. Hence the 3:1 ratio.
No, this calculator assumes complete dominance where any individual with at least one dominant allele shows the dominant phenotype. For incomplete dominance (where the heterozygote shows a blended phenotype), use our Incomplete Dominance Calculator which gives the 1:2:1 phenotype ratio.
Roboculator Team
The Roboculator Team explains calculations, planning tools, and practical formulas in clear language for real-life situations.
How helpful was this calculator?
Be the first to rate!
Dihybrid Cross Calculator
Punnett Square Calculators
Test Cross Calculator
Punnett Square Calculators
Incomplete Dominance Calculator
Punnett Square Calculators
Codominance Calculator
Punnett Square Calculators
Sex-Linked Trait Calculator
Punnett Square Calculators
Chi-Square Goodness of Fit Calculator
Punnett Square Calculators
