• 13 parts
  • Checked October 2026

Punnett Square Labeled

The square a genetics class fills in, drawn twice: one trait in four boxes, two traits in sixteen.

Punnett Square Labeled

Name Date

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1 2 3 4 5 6 7 8 9 10 11 12 13
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Write the name of each numbered part.Answer key

  1. Genotype of a parent
  2. Dominant allele
  3. Recessive allele
  4. Homozygous dominant
  5. Heterozygous
  6. Homozygous recessive
  7. Dominant phenotype
  8. Recessive phenotype
  9. Gamete
  10. Round yellow seeds
  11. Round green seeds
  12. Wrinkled yellow seeds
  13. Wrinkled green seeds

Drawn for this site on 2026-10-03 by a script from the table in this dataset. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Next: meiosis, where the alleles are dealt out

All 13 parts on the diagram

Show the list

One trait: Rr crossed with Rr 8

  1. Genotype of a parent The two alleles one parent carries. Both parents here are Rr.
  2. Dominant allele Written as a capital letter. One copy is enough for its trait to show.
  3. Recessive allele Written as a small letter. Its trait shows only when both alleles are recessive.
  4. Homozygous dominant Two copies of the dominant allele. One box in four here.
  5. Heterozygous One dominant and one recessive allele. Two boxes in four here.
  6. Homozygous recessive Two copies of the recessive allele. Only this box shows the recessive trait.
  7. Dominant phenotype The trait three boxes in four show. Here it is a round seed.
  8. Recessive phenotype The trait one box in four shows. Here it is a wrinkled seed.

Two traits: sixteen boxes 5

  1. Gamete One allele of each gene, from one parent. Each parent here makes four kinds.
  2. Round yellow seeds Both dominant traits show. Nine of the sixteen boxes are in this class.
  3. Round green seeds Round shows, with the recessive seed color. Three of the sixteen boxes.
  4. Wrinkled yellow seeds Wrinkled shows, with the dominant seed color. Three of the sixteen boxes.
  5. Wrinkled green seeds Both recessive traits show. Only one box in sixteen, rryy.

How this list was compiled: Every name, letter and ratio checked on 2026-10-03 against Nature Education, Scitable: Inheritance of Traits by Offspring Follows Predictable Rules (https://www.nature.com/scitable/topicpage/inheritance-of-traits-by-offspring-follows-predictable-6524925/) and Gregor Mendel and the Principles of Inheritance (https://www.nature.com/scitable/topicpage/gregor-mendel-and-the-principles-of-inheritance-593/); Wikipedia, text only: Punnett square, Dihybrid cross, Monohybrid cross; and the Talking Glossary of the National Human Genome Research Institute: Allele, Genotype, Phenotype, Homozygous, Heterozygous, Dominant, Recessive, Gamete (https://www.genome.gov/genetics-glossary). Licence: own work

The drawing: Drawn for this site on 2026-10-03 by a script from the table in this dataset; nothing traced. Licence: own work

How it works

A Punnett square labeled part by part: the alleles of each parent along the top and down the side, the genotype in every box, and the phenotypes that follow. Read the names, then press Quiz me.

Read the full guide

Read the square for one trait

Both parents here are Rr. Each hands one allele to an offspring, so R and r stand along the top and down the side. Every box pairs the letter above it with the letter beside it: RR, Rr, Rr, rr. R, a round seed, is dominant, so three boxes in four give round seeds and one gives wrinkled: a ratio of 3 to 1.

Two traits at once

Two RrYy parents each make four kinds of gametes: RY, Ry, rY and ry. The sixteen boxes fall into four classes in the ratio 9 to 3 to 3 to 1.

  • In a box the capital letter is written first: Rr.

Questions and answers

How do you read a Punnett square?

Find one parent's alleles along the top and the other's down the side. Each inside box joins the letter above it and the letter beside it. That pair of letters is one possible genotype of the offspring.

What is the difference between genotype and phenotype?

The genotype is the pair of alleles, written as letters such as Rr. The phenotype is the trait that shows, such as a round seed. RR and Rr are different genotypes with the same phenotype.

What do homozygous and heterozygous mean?

Homozygous means the two alleles are the same, RR or rr. Heterozygous means they differ, Rr. A heterozygous box shows the dominant trait, because one dominant allele is enough.

Why is the ratio 3 to 1?

Of the four boxes, RR and the two Rr each hold at least one dominant allele, so three show the dominant trait. Only rr shows the recessive one. With two traits the sixteen boxes give 9 to 3 to 3 to 1.

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