Dihybrid Cross Calculator

Use this free Dihybrid Cross Calculator to calculate the probability of gene inheritance for your offspring. This tool also generates a chance percentage table for each gene combination using two traits and four alleles simultaneously.

What Is Dihybrid Cross?

In genetics, a dihybrid cross is defined as:

A cross between two individuals (father and mother) involving two traits that are controlled by different genes.

Possible Combinations in a Dihybrid Cross

For parent genes with genotype AaBb, there are four possible gamete combinations from each parent:

Half of the gametes inherit dominant alleles, while the other half inherit recessive alleles.
The parents can produce four gamete types: AB, Ab, aB, ab, each representing approximately 25% of the total.

Dihybrid Punnett Square

A Punnett square is a table used to predict the possible genotypes of offspring based on the genotypes of both parents. Below is an example of a basic dihybrid 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

This free Dihybrid Cross Calculator can quickly calculate genetic variations for your offspring in terms of Punnett square combinations.

Additionally, you can also use a Blood Type Calculator to predict Punnett square combinations for your baby's blood group.

How to Do Punnett Squares with 2 Traits?

Punnett squares with two traits involve a 4×4 table, showing different probabilities that can be tricky to calculate manually.

This complexity arises because:

There are 16 possible gamete combinations.
Up to 9 different genotype possibilities exist.
A total of 81 possible dihybrid Punnett square combinations may arise.
Each parent has 4 different alleles contributing to inheritance.

Luckily, our dihybrid cross calculator handles these calculations automatically, saving you time and effort.

Dihybrid Cross Inheritance Example

Let’s illustrate dihybrid inheritance with a practical example:

Scenario:

The mother has blonde, curly hair, and the father has straight, light hair. We want to predict the Punnett square gene combinations for their child.

Traits Considered

Hair color
Hair type

For simplicity, let’s assign the following alleles:

A – Curly hair (dominant)
a – Straight hair (recessive)
B – Dark hair (dominant)
b – Light hair (recessive)

We assume the father produces the alleles ab (homozygous for straight and light hair). The mother can contribute the alleles Ab (curly and light hair).

4×4 Punnett Square for Two Traits

♂️\♀️	Ab	Ab	ab	ab
ab	Aabb	Aabb	aabb	aabb
ab	Aabb	Aabb	aabb	aabb
ab	Aabb	Aabb	aabb	aabb
ab	Aabb	Aabb	aabb	aabb

From this Punnett square, you can calculate the probability of each genotype and predict the inheritance patterns for the offspring.

Phenotype

Phenotype refers to the observable traits of an individual, such as eye color, hair color, nose shape, body shape, and other visible characteristics.

Genotype

Genotype represents the genetic makeup inherited from the parents, which determines the phenotype of the offspring.

Genotype and Phenotype Ratios

For a simple dihybrid example with two traits:

Aabb = Ab
aabb = ab

The probability of each genotype is 0.5:0.5 (or 1:1), meaning 50% of the offspring will have the Aabb genotype and the remaining aabb.

For the Punnett square combinations, the raw ratios might be:

6.25 : 12.5 : 6.25 : 12.5 : 25 : 12.5 : 6.25 : 12.5 : 6.25

To simplify, divide all ratios by the smallest value (6.25):

1 : 2 : 1 : 2 : 4 : 2 : 1 : 2 : 1

How the Dihybrid Cross Calculator Works

This dihybrid Punnett square calculator allows you to predict offspring traits by providing the following inputs:

Inputs:

Select the traits for both parents (father and mother)
Click the "Calculate" button

Outputs:

Probability of dihybrid crosses for each allele pair
Genotypes and phenotypes of all possible offspring combinations

FAQs

What is the difference between Monohybrid and Dihybrid Cross?

A monohybrid cross involves only one trait in the F1 generation, whereas a dihybrid cross involves two traits simultaneously.

What is the genotypic ratio of a Dihybrid Cross?

For a typical dihybrid cross, the genotype ratio is 1:2:1:2:4:2:1:2:1 after simplifying the Punnett square outcomes.

What is an allele?

An allele is a specific version of a gene located at a particular position (locus) on a chromosome. You can also explore this using an allele frequency calculator.

Which gene is dominant?

Dominance refers to the relationship between alleles. When two different alleles are present, the allele that is expressed in the phenotype is dominant, while the other is recessive.

What is the difference between a gene and an allele?

A gene is a segment of DNA that encodes a trait, while an allele is a specific form of that gene.

What is the Law of Dominance?

Proposed by Gregor Mendel, the Law of Dominance states:

"When parents with pure, contrasting traits are crossed, only one form of the trait appears in the next generation. The hybrid offspring will exhibit only the dominant trait in the phenotype."

Conclusion

Genetic crossover allows random shuffling of alleles during gamete formation, producing offspring with unique combinations. Predicting these combinations can be efficiently done using a dihybrid cross calculator, which helps understand the potential genotypes and phenotypes of a child.

References

Wikipedia: Punnett square, Zygosity, Monohybrid cross, Reginald Punnett
Khan Academy: Probabilities in genetics, Alleles and genes, The law of segregation
Lumen Learning: Non-Mendelian Punnett Squares, Multiple Alleles, Penetrance and Expressivity