Genetics Investigation Lab

7th Grade Science

Welcome to the
Genetics Lab

Today you are not just science students. You are genetic investigators.

🎯 Learning Targets Open Case File → Today's Mission

Today's Learning Target

What Are We Learning?

📘 Missouri Learning Standard

LS3 — Heredity: Inheritance and Variation of Traits

We will investigate how traits are passed from parents to offspring and how inherited genetic information can create similarities and differences among offspring.

🎯 I Can Statement

I can explain how traits are inherited from parents and use genetic information to predict possible traits in offspring.

🧬 By the End of Class, I Can...

✅ Identify the difference between a gene, allele, genotype, and phenotype.

✅ Explain how offspring inherit genetic information from their parents.

✅ Use a Punnett square to predict possible offspring genotypes.

✅ Explain why siblings can have the same parents but different combinations of traits.

✅ Use genetic evidence to solve an inheritance problem.

Case Entry • Do Now

Before We Open the Lab...

👀 How can brothers and sisters have the SAME parents but look very different?

DO NOW — 4 Minutes

Answer the following on your paper. You do not need to know the scientific answer yet.

Name two traits that people can inherit from their parents.
If two parents have brown eyes, do you think it is possible for their child to have a different eye color? Explain your thinking.
What do you think the word genetics means?

Do Now Timer

4:00

💬 Turn & Talk: What is one trait you think you inherited from someone in your family?

Mission Briefing

Your Mission Today

1. Investigate

Discover how traits move from parents to offspring.

2. Predict

Use Punnett squares to predict possible offspring.

3. Solve

Use genetic evidence to solve a mystery.

4. Create

Use genetics to invent your own organism.

Essential Question:

How do genes help explain why offspring are similar to — but not identical to — their parents?

Lab Training

The Genetics Vocabulary You Need

🧬 Gene

A section of DNA that contains instructions for a characteristic.

🔤 Allele

A version of a gene.

Example: B or b

🔎 Genotype

The allele combination an organism has.

Example: Bb

👀 Phenotype

The observable trait.

Example: brown eyes

⬆ Dominant

An allele that can appear in the phenotype when one copy is present.

⬇ Recessive

Usually appears in the phenotype when two recessive copies are present.

⚠️ Important: In today's classroom model, we will use simplified single-gene traits to learn inheritance patterns. Real human traits are often much more complicated.

Checkpoint 1

Genotype or Phenotype?

Which one is a genotype?

Which one is a phenotype?

Investigation 1

Build-a-Child Genetics Lab

Two fictional parents are shown below. Each child receives one allele from each parent.

Parent A

Hair

Dimples

Widow's Peak

Freckles

Parent B

Hair

Dimples

Widow's Peak

Freckles

Generate One Possible Child

Click below. The computer will randomly select one allele from each parent.

Your genetic profile will appear here.

💡 Discuss: If we generate another child from these SAME parents, will the child always have the same genotype? Why or why not?

Investigation 2

Punnett Square Prediction Lab

Punnett squares help geneticists determine the possible allele combinations offspring might inherit.

Case: Bb × Bb

Each parent has the genotype Bb.

	B	b
B	BB	Bb
b	Bb	bb

What percentage of the four boxes are:

BB?
Bb?
bb?

BB = 25%
Bb = 50%
bb = 25%

🚨 Genetics Myth Alert: 25% does NOT mean that if a family has four children, exactly one must have that genotype.

It means each offspring has a probability of inheriting that combination.

Investigation 3

The Genetics Crime Scene

🚨 CASE FILE #007: One of these genetic records cannot be correct.

👩

Mother
Genotype: Bb

👨

Father
Genotype: bb

Possible Children?

Which child has a genotype that is impossible from these parents?

Child D: BB is impossible.

The father has genotype bb. That means he can only contribute a lowercase b allele. Therefore, none of his children can receive a capital B from him.

Investigation 4

Work Backward Like a Geneticist

Mystery

A fictional trait uses:

B = dominant allele
b = recessive allele

Two parents BOTH show the dominant phenotype.

Their child shows the recessive phenotype.

What must be true about BOTH parents?

Creation Lab

Create a Creature 🐉

Now use your genetics knowledge to create a fictional organism.

Trait 1 — Wings

W = wings
w = no wings

Trait 2 — Horns

H = horns
h = no horns

Trait 3 — Glow

G = glowing skin
g = no glow

Trait 4 — Tail Spikes

T = spikes
t = smooth tail

Parent Creatures

Parent A: Ww Hh gg Tt

Parent B: ww Hh Gg tt

🥚

Your creature's genetic profile will appear here.

✏️ Your Team Challenge: Draw your creature on paper.

Label:
• genotype
• phenotype
• allele inherited from Parent A
• allele inherited from Parent B

Think Like a Scientist

What Did We Discover?

Question 1

Why don't all siblings look identical?

Question 2

What is the difference between genotype and phenotype?

Question 3

Why does a Punnett square show probability instead of certainty?

Scientists use evidence to explain patterns.

What genetic pattern did YOU notice today?

Final Case Report

🧬 Exit Ticket

Complete these independently before leaving the lab.

1. Vocabulary

What is the difference between genotype and phenotype?

2. Genetics Reasoning

Two siblings have the same parents but look different. Explain how this can happen using what you learned today.

3. Punnett Square Thinking

Parents have genotypes: Bb × bb.

Which genotype could NOT appear in their offspring?

4. Reflection

What is one idea about genetics that surprised you today?

Complete the investigation first.

CASE CLOSED 🧬

Today's geneticists investigated inheritance, predicted outcomes, analyzed evidence, and created an organism using genetic information.

Scientists don't just memorize answers. They discover patterns and explain them.

Welcome to the Genetics Lab