Dihybrid Cross Calculator
Analyze the genetic outcomes of crossing two traits. Enter the parental genotypes for Gene 1 (A/a) and Gene 2 (B/b) to generate an intetive 4x4 Punnett square.
Parental Genotypes
Select the genotype for both parents for Gene 1 and Gene 2.
Parent 1 (Mother)
Parent 2 (Father)
4×4 Punnett Square
| AB | Ab | aB | ab | |
|---|---|---|---|---|
| AB | AABB | AABb | AaBB | AaBb |
| Ab | AABb | AAbb | AaBb | Aabb |
| aB | AaBB | AaBb | aaBB | aaBb |
| ab | AaBb | Aabb | aaBb | aabb |
Offspring Probabilities
Phenotypic Ratio (Simple Dominance)
Top Genotypes
Independent Assortment Rule
A classic dihybrid cross between two double heterozygotes (AaBb × AaBb) will always yield a chateristic 9:3:3:1 phenotypic ratio.
Dihybrid Cross 9:3:3:1 Phenotype Reference Table
| Phenotype Combination | Genotype Representation | Mendelian Ftion | Probability (%) |
|---|---|---|---|
| Double Dominant | A_B_ | 9 / 16 | 56.25% |
| Gene 1 Dominant, Gene 2 Recessive | A_bb | 3 / 16 | 18.75% |
| Gene 1 Recessive, Gene 2 Dominant | aaB_ | 3 / 16 | 18.75% |
| Double Recessive | aabb | 1 / 16 | 6.25% |
Calculation Methodology & Biological Principles
Law of Independent Assortment
During metaphase I of meiosis, non-homologous chromosome pairs align randomly at the metaphase plate, segregating unlinked genes independently into haploid gametes.
Forked-Line Method Equation
P(A_B_) = P(A_) × P(B_) = (3/4) × (3/4) = 9/16
P(A_bb) = P(A_) × P(bb) = (3/4) × (1/4) = 3/16
P(aaB_) = P(aa) × P(B_) = (1/4) × (3/4) = 3/16
P(aabb) = P(aa) × P(bb) = (1/4) × (1/4) = 1/16
Frequently Asked Questions
What is a Dihybrid Cross? ▼
A dihybrid cross is a genetic breeding experiment between two individuals that analyzes the inheritance patterns of two distinct, unlinked gene traits simultaneously.
What is Mendel's Law of Independent Assortment? ▼
Mendel's Second Law states that alleles of two or more different genes assort independently of one another into gametes during meiosis, provided the genes are located on different chromosomes.
What is the classic phenotypic ratio of a dihybrid cross? ▼
Crossing two double-heterozygous parents (AaBb × AaBb) yields a classic Mendelian 9:3:3:1 phenotypic ratio (9/16 double dominant, 3/16 single dominant/recessive, 3/16 single recessive/dominant, 1/16 double recessive).
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