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Punnett Square Worksheet Generator

Create A4 genetics worksheets with 2 × 2 and 4 × 4 Punnett squares, from crosses with the genotypes given to problems where you work out the parents, plus an answer key with the gametes, the completed square and the ratios.

✓ Grade 10✓ 5 cross types✓ 2 × 2 and 4 × 4 squares✓ Answer key with ratios

🪄 Wizard: Add Problems to the Worksheet

1. Cross type:

2. Difficulty level:

3. Quantity:

💡 Learning goal: Monohybrid crosses with one dominant and one recessive allele, like Mendel's peas: Mendel's first two laws, the test cross and the 3:1 and 1:1 ratios. Grade 10.
Level 1: Genotypes given: The genotypes of both parents are given: write their gametes, complete the square and work out the genotypic and phenotypic ratios.

📋 Problems on the Worksheet

✨ No problems yet. Choose the options above and click “Add to Worksheet”.

⚙️ Format & Print Options Student worksheet and answer key

Custom worksheet title:

Exercise order:

Sheets to print:

📄

📚 Teaching Guide: Punnett Squares and Mendelian Genetics

A Punnett square predicts the offspring of a cross: each parent's gametes along the edges and, in every box, the genotype they make together. This free Punnett square worksheet generator builds A4 genetics worksheets for Grade 10 with real traits, from Mendel to Morgan, and a full answer key.

🌱 Complete dominance

Mendel's pea traits, guinea pig fur, fruit fly wings and albinism: the 3:1 and 1:1 ratios and the test cross.

🌸 Incomplete dominance and codominance

Pink snapdragons, blue Andalusian chickens, roan cattle and the MN blood groups: the heterozygote shows in the phenotype.

🩸 ABO blood groups

Three alleles, two codominant and one recessive: which groups a couple’s children can have and what a child with group O reveals.

♀♂ Sex-linked inheritance

Colour blindness, haemophilia and Drosophila eye colour: carrier women, men with a single allele and different ratios in sons and daughters.

▦ Dihybrid 4 × 4 squares

Four gametes from each parent, the 16-box square and Mendel's law of independent assortment: 9:3:3:1, 1:1:1:1 and 3:3:1:1.

✅ Full answer key

Gametes, the completed square with the phenotype of every box, and the simplified genotypic and phenotypic ratios as fractions and percentages.

❓ Frequently Asked Questions about the Punnett Squares

How do you fill in a Punnett square?

Write the mother's gametes down the left and the father's along the top; each box joins one gamete from each side and gives the offspring's genotype. Then count the boxes of each genotype and phenotype to get the ratios. A 2 × 2 square is for one gene and a 4 × 4 square for two.

Are the ratios in the answer key right?

Yes. The generator works out the gametes and fertilisation of every cross, fills the square box by box and counts the genotypes and phenotypes that come out. Ratios are given in their simplest form, as fractions and as percentages.

What changes with each difficulty level?

At level 1 the genotypes are given. At level 2 the parents are described by their phenotype, so students write the genotypes first. At level 3 students work out the parents' genotypes from the offspring: the generator only sets problems with exactly one answer.

Are the traits real?

Yes: Mendel's pea traits, the Drosophila eye colour Morgan studied, colour blindness, haemophilia A, albinism and the ABO and MN blood groups. The two genes of every dihybrid problem are on different chromosomes, so they are inherited independently.

Which grade is it for?

For Mendelian genetics in Grade 10 biology. The dihybrid and sex-linked problems also work as revision in Grade 11.

Is any student data sent to a server?

No. Every problem is generated in your browser and no student data is stored.

📋 Problems on the Worksheet

📚 Teaching Guide: Punnett Squares and Mendelian Genetics

🌱 Complete dominance

🌸 Incomplete dominance and codominance

🩸 ABO blood groups

♀♂ Sex-linked inheritance

▦ Dihybrid 4 × 4 squares

✅ Full answer key

❓ Frequently Asked Questions about the Punnett Squares

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