Punnett Square Calculator - Stroke and Gene Calculator (2023)

How does property inheritance work? The Punnett Squared Calculator gives you an answer to these and many other questions. It is very useful when you want to calculate thegenotypic ratio, phenotypic ratio, or if you are looking for a simple, ready-to-use table of dominant and recessive traits. In addition, you can use our Punnett square maker to calculate the probability of inheriting a rare and recessive genetic disease.

Hey, maybe you're looking for a more advanced one.Dihybrid cross calculator(with 2 characters and 4 alleles) or one extreme, giganticTrihybrid Crossover Calculator(a Punnett square with three lines)?

This Punnett square generatorwill teach you the basics of genetics, and takes you step-by-step through creating your own genetic square. Continue reading!

How do I make a Punnett square? - Examples

Creating a simple 1-trait gene diagram is extremely easy! you have to remember thatnot all genes can be usedto create a Punnett square. Here is a short list of rules to follow:

  • Given traits must be inherited independently (their genes cannot be close together in the genome);
  • External factors cannot influence the inheritance of a gene; And
  • A specific trait only needs to be defined by the alleles that we will use in the genetic table.

✅ Blood group inheritance is a good example of a trait that is perfect for use in the Punnett Squared Calculator.

❌ The size of a childcannot be predicted using the Punnett squared method- There are too many variables and genes that affect this trait.

Traits are inherited through genes, the cell's memory banks. Each gene has two versions called alleles. We use capital letters fordominant Alleles(A) and lowercase forrecessive alleles(To). Dominant alleles are superior in terms of strength: if a dominant allele is present, the trait that carries it will always be apparent. The characteristics of the recessive alleles are only visible when no dominant alleles are present.

(Video) Punnett Squares - Basic Introduction

If you already know your blood type... why not see who you could donate it to? 🩸Try ourBlood Donor Calculator.

Punnett Square Calculator in Practice

Suppose we need to know the probability that our patients' babies will inherit a genetic disorder called inheritancecystic fibrosis.

  1. Find out about the form of inheritance.

autosomal recessive. (Autosomal inheritance means that the genes described are on the regular chromosomes [1-22] and not on the sex chromosomes [X,Y])

  1. Study the genetics of the parents.

Both families have children with cystic fibrosis. Both parents are healthy, howevercan still be carrierssince the disease is inherited in an autosomal recessive manner.

  1. Fill in the square!For this particular case, we need two Punnett squares.
  • A - healthy and dominant allele
  • a - recessive allele of cystic fibrosis

the first situation: Both parents are carriers.

♂️\♀️

A

A

A

AA

AA

A

AA

AA

There is a 25% (1/4) chance of giving birth to a child with cystic fibrosis.
On average, 75% of children born to these parents are healthy: 2/3 of them will be carriers and 1/3 will not inherit CF alleles.
(If percentages get confusing, try thepercent tool.)

second situation: Only one parent is a carrier.

♂️\♀️

A

A

A

AA

AA

A

AA

AA

In this situation, 100% of babies are born healthy. 50% of them inherit one wrong allele, making them carriers.

Play around with our Punnett Squared Calculator and try out all the possible options!

(Video) Punnett Square Basics | Mendelian Genetic Crosses

Genotypic ratio and phenotypic ratio

The phenotype describes the appearance, i.e. what is visible. The genotype describeshiddengenetic properties of a trait.
What is the difference? Why does this matter?
Let's look at the following genetic table.

♂️\♀️

A

A

A

AA

AA

A

AA

AA

Now let's calculate the genotypic and phenotypic ratios:

Result

genotype

phenotype

AA

AA

A

AA

AA

A

AA

AA

A

Proportion genotypically

  • AA : AA : AA = 1 : 2 : 1

Phenotypic Ratio:

  • A : a = 3 : 1

because alleleAis recessive if it occurs with a dominant allele, the trait it carriesit is not visible, but the allele is still there and ready to be possibly inherited in the future.

Autosomal alles - homozygot oder heterozygot?

Here are some basic definitions that can be crucial for using the genetic calculator correctly:

  • homozygot dominant- Where a set of alleles of a gene describes a specific trait. We can use this concept when both alleles are dominant (AA).

  • homozygous recessive- We use it when the two alleles described are recessive (AA)

  • heterocigoto- We use it when an allele is recessive (A) and the other is dominant (A).

(Video) How to Use Punnett Squares

Mendelian legacy

The basic rules of genetics were created by Gregor Mendel in 1865 thanks to his simple experiments with peas. During this era, mankind had no microscopes, complex scientific technology, or even the slightest notion of genes. With simple experiments and insightful observations, he was able to draw conclusions that are still useful today; No wonder they call itthe father of genetics.

  1. The characteristics are uniform (red color versus yellow color);
  2. There are two versions of each gene (we'll call them nowAlleles);
  3. There are types of alleles that are superior to the other types (dominant alleles);
  4. Alleles separate randomly;
  5. The probability that each allele is inherited is equal; And
  6. Genes are inherited independently.

A few centuries later, we can certainly say that Mendel was not entirely right: some of the genesSohnThey are inherited together because of their proximity on the chromosome. Next to,Some of the genes are codominant: Two different dominant alleles can coexist and be visible in the phenotype at the same time. Blood type inheritance is a prime example of this, as the dominant A and B alleles work together to create blood type AB.

Types of Punnett squares

Our Punnett Square Maker works with autosomal alleles (chromosomes 1-22) but can be used for other things as well.

let's think about itX-Linked Diseases: Diseases that are inherited only through the female line of the family. Every woman has two different X chromosomes, which she inherited from her parents. If one of them is defective or sick, the second, healthy one, can take over its function. However, every man is equipped with a single X chromosome, so even a single wrong allele can cause a disease in men but not in women.

hemophiliaIt is a rare genetic disorder linked to the X chromosome. We would like to know what is the likelihood of a male patient with hemophilia having a baby with this disorder. Your partner is healthy and has no trace of the disease in your family.

(Video) A Beginner's Guide to Punnett Squares

  • XD - healthy X chromosome;
  • Xd - X chromosome containing the hemophilia gene; And
  • Y-Y-Chromosome.

♂️\♀️

XDD

XDD

xd

XdXD

XdXD

Y

XDY

XDY

We can see that clearlyAll of the patient's children will be healthy. However, all of her daughters will be carriers, andcan transmit the disease to the next generation. All your children will be completely free from the disease.

frequently asked Questions

How do you use a Punnett square?

  1. Find the genotypes of both parents. Consider whether they are homozygous dominant, recessive, or heterozygous.
  2. Fill in the first column and row with the alleles of the parents.
  3. Mix each allele of one parent with the alleles of the other.

For example, if both parents are heterozygous, Punnett square looks like this:

♂️\♀️

A

A

A

AA

AA

A

AA

AA

There is a 75% chance of carrying the dominant allele.

How to find genotype and phenotype from a Punnett square?

  1. Look at the result of Punnett square.
  2. To find possible genotypes, locate different combinations of alleles -AA,AA, ÖAA. You can determine the genotypic ratio by counting the number of occurrences of each genotype.
  3. You can use the possible genotypes to evaluate the phenotypes. For example, if the alleleAis dominant andAis recessive:
  • genotypeAAis expressed by the phenotypeA;
  • genotypeAAis expressed by the phenotypeA; j
  • genotypeAAis expressed by the phenotypeA.

How do you know if a genotype is heterozygous or homozygous?

An organism with two different alleles at one locus (a dominant and a recessive -AA) have aheterozygous genotype.

homozygous genotypemeans the presence of two identical alleles (both normal or identically mutated -AAÖAA).

(Video) Punnett Squares and Sex-Linked Traits

Wozu saying ein Punnett-Square?

Using Punnett square we can find the probability of obtaining certain genotypes and phenotypes as a result of crossing. While it is a good method for learning Mendel's rules of inheritance, it is often not applicable to the study of humans, as multiple genes often determine human traits. For example, more than ten genes affect eye color!

Videos

1. How to determine Genotypic Ratio and Phenotypic Ratio in monohybric crossing using punnett square
(Madam EM)
2. Learn Biology: How to Draw a Punnett Square
(mahalodotcom)
3. Example punnet square for sex-linked recessive trait | High school biology | Khan Academy
(Khan Academy)
4. How to find phenotipic ratio in F2 generation
(Nikolay's Genetics Lessons)
5. How to solve sickle-cell anemia problem using Punnett square
(Nikolay's Genetics Lessons)
6. 12B05 - Principles of Inheritance and Variation - Punnett Square
(Avanti Gurukul)

References

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