What is a Punnett Square?
Definition: a square diagram that is composed of a grid of usually four boxes and is used to calculate and depict all the combinations and frequencies of the different genotypes and phenotypes among the offspring of a cross in accordance with Mendelian inheritance
Punnett Square Examples Through a Lab Activity
Blood types show co-dominance but with 3 different types of alleles, as we learned in the slide show and guided notes. Hospitals use blood types to match babies to their parents and to identify criminal suspects as well.
Let’s do a little detective work! Using movable alleles with a partner, solve the following mysteries! Remember what we know about blood types.
- To be blood type O, you must inherit two recessive o alleles.
- To be blood type A, you can be AA, or heterozygous with A and the recessive O. (Ao)
- To be blood type B, you can be BB, or heterozygous with B and the recessive (Bo)
- To be blood type AB, you must have one A allele and one B allele.
Family Mysteries Blood Type Activity Laboratory Proper:
NGSS Standards Covered
- MS-LS1-4 Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction of animals and plants respectively.
- MS-LS1-5 Construct a scientific explanation based on evidence for how environmental and genetic factors influence the growth of organisms.
- MS-LS3-1.Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation.
- MS-LS4-4 Construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individuals’ probability of surviving and reproducing in a specific environment.
The Punnett Square Learning Objectives
- Organize observations and data into tables, charts and graphs.
- Explain Co-Dominance, Incomplete Dominance, and Blood Typing.
I Can Statement
I can solve non-Mendelian Punnett squares and determine ratios and probabilities of offspring.
Punnett Square Vocabulary:
- Gender
- Co-Dominance
- Incomplete Dominance
- Blood Type
Here are the Files Downloadable Files for the Create a Monster Activity
- 5-7b Lab Activity SE - The Punnett Square (Docx)
- 5-7b Lab Activity SE - The Punnett Square (PDF)
- 5-7b Lab Activity TE - The Punnett Square (Member Only Docx)
- 5-7b Lab Activity TE - The Punnett Square (Member Only PDF)
Blood Type Activity Lab Materials:
Materials for each partner pair:
- Set of blood type alleles
- Copy of Punnett workspace
Materials for each student:
- Student worksheet
- Pencil
Family Mysteries Blood Type Activity Procedure
Read each mystery. With your partner, select the correct alleles and lay them on the large Punnett square workspace, and then answer the questions in the story.
Use your worksheet to take any notes you might need to refer to answer the questions.
Data and Results
Mystery #1 Blood Lab Activity
Yes, Sir, That’s My Baby!
The Smiths and the Browns were both having babies! Mrs. Smith and Mrs. Brown shared a room in the hospital after the babies were born. Both babies were adorable- and looked very similar. As both families prepared to head home, Mrs. Smith got a weird feeling that the babies had been mixed up. After a few days, Mrs. Smith insisted on getting blood tests to make sure the right baby was at the right house. Use this information, and your allele markers to create the Punnett squares on the workspace for the Smiths and Browns.
Here are the results of the blood tests.
- Mrs. Smith - Type O
- Mrs. Brown - Type A
- Mr. Smith - Type AB
- Mr. Brown - Type A
- Baby at the Smith house - Type O
- Baby at the Brown House - Type A
Use the Punnett workspace to determine the following:
- What is Mrs. Smith’s genotype?
- What is Mr. Smith’s genotype?
- What are Mrs. Brown’s possible genotypes?
- What are Mr. Browns’ possible genotypes?
Now look at the Punnett square possibilities. Did the families go home with the correct babies? Why or why not?
Mystery #2 Blood Lab Activity
Money Matters
Mr. Rich was, in fact, very rich! When he died, he left all his money and property to his two children. His obituary, as is common, was in the newspapers. A few days later, a man named Joe showed up claiming to be Mr. Rich’s long-lost son and demanded his share of the inheritance. The lawyers were not convinced that Joe was Mr. Rich’s son, so they ordered blood tests for all of them. Here’s what we know:
- Mr. Rich’s blood type - AB
- Mrs. Rich’s blood type - A
- Both children of the Rich family - B
- Joe- claiming to be the long-lost son of Mr. Rich (but not of Mrs. Rich) - Blood type O
Use the Punnett workspace to determine the following:
- What is the only possible genotype Mrs. Rich could have?
(Hint- this time, start with the offspring and the father on the Punnett workspace, to figure out the MOTHER’s second allele.)
- Now use the Punnett workspace to determine the genotypes of the children of Mr. and Mrs. Rich.
- Finally, use the Punnett workspace to determine if Mr. Rich could have a child that is type O. Remember O is recessive and must have 2 (oo) alleles.
Explain your findings.
Mystery #3 Blood Lab Activity
Bungled Bracelets!
The newborn nursery in a hospital is a busy and noisy place. Each baby has its own bassinette, and each baby has a bracelet that identifies it. However, somehow three babies wriggled out of their bracelets, and no one knows which family each baby belongs to. HELP!
- The Mendels have blood types of O and AB
- Baby A is type AB
- The Darwins have blood types of A and O
- Baby B is type O
- The Punnetts have blood types of A and B
- Baby C is type B
Use the Punnett workspace to explore all possible combinations to be sure the babies go home with the right parents! Explain!
(Hint)- The Mendels only have one possible Punnett square.
The Darwins have two possible Punnett squares.
The Punnetts have four possible Punnett squares.
- Who are the parents of Baby A?
- Who are the parents of Baby B?
- Who are the parents of Baby C?
Here is your Free Content on The Punnett Square Lesson
The Punnett Square Blood Types Activity Worksheet - PDFs
- 5-7a Assignment SE - The Punnett Square (FREE)
- 5-7a Assignment TE - The Punnett Square ( Members Only )
- 5-7b Assignment SE - The Punnett Square (FREE)
- 5-7b Assignment TE - The Punnett Square ( Members Only )
- 5-7a Bell Work SE - The Punnett Square (FREE)
- 5-7a Bell Work TE - The Punnett Square ( Members Only )
- 5-7b Bell Work SE - The Punnett Square (FREE)
- 5-7b Bell Work TE - The Punnett Square ( Members Only )
- 5-7a Exit Quiz SE - The Punnett Square (FREE)
- 5-7a Exit Quiz TE - The Punnett Square ( Members Only )
- 5-7b Exit Quiz SE - The Punnett Square (FREE)
- 5-7b Exit Quiz TE - The Punnett Square ( Members Only )
- 5-7 Guided Notes SE -The Punnett Square (FREE)
- 5-7 Guided Notes TE -The Punnett Square ( Members Only )
- 5-7a Lesson Plan - The Punnett Square ( Members Only )
- 5-7b Lesson Plan - The Punnett Square ( Members Only )
- 5-7a Slide Show - The Punnett Square ( Members Only )
- 5-7b Slide Show - The Punnett Square ( Members Only )
- 5-7 Online Activities - The Punnett Square ( Members Only )
- 5-7 Vocabulary Worksheet SE - The Punnett Square (FREE)
- 5-7 Vocabulary Worksheet TE - The Punnett Square ( Members Only )
The Punnett Square Blood Types Activity WorksheetWorksheets - Word Docs & PowerPoints
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Unit 5 - Genetics
- 5-1 Introduction to Genetics
- 5-1a Introduction to Genetics
- 5-1b Introduction to Genetics - Asexual vs Sexual Reproduction
- 5-2 Early Ideas About Heredity
- 5-3 Mendel's Experiment
- 5-3a Mendel's Experiment
- 5-3b Mendel's Experiment
- 5-4 Mendel's Laws of Inheritance
- 5-5 Chromosomes
- 5-5a Chromosomes
- 5-5b Chromosomes
- 5-6 Alleles and Genes
- 5-7 The Punnett Square
- 5-7a The Punnett Square
- 5-7b The Punnett Square
- 5-8 Pedigree
- 5-9 Genetic Disorder
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