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Mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. Germline mutations occur in the eggs and sperm and can be passed on to offspring, while somatic mutations occur in body cells and are not passed on.

Images and animations are courtesy of the National Human Genome Research Institute's Talking Glossary (

Materials for Mutations


Addition and Deletion Mutations

Description: An animation and practice problems on addition and deletion mutations


Description: Explore how changing the DNA sequence can change the amino acid sequence of a protein


Genetic Mutation

Description: Information on gene mutations, including the different types, causes, effects, and estimating mutation rates

Lives in the Balance: Why Do We Hold Onto Potentially Harmful, Disease-Causing Mutations?

Description: The persistence of heritable disease raises an evolutionary paradox. When DNA goes awry, and a harmful mutation sprouts up that affects survival, why are these not simply purged from a population over generations?

Mutant Fruit Flies

Description: An activity that explores how gene mutations can affect the physical characteristics of fruit flies

What Is a Gene Mutation and How Do Mutations Occur?

Description: Information on gene mutations

What is a Mutation?

Description: A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke.


Gene Machine - The Lac Operon

Description: Build a gene network! The lac operon is a set of genes which are responsible for the metabolism of lactose in some bacterial cells. Explore the effects of mutations within the lac operon by adding or removing genes from the DNA.

Interactive Tutorials

Mutations are Changes in Genetic Information

Description: An interactive Web site exploring basic concepts of gene mutations through historical discovery

Some Types of Mutations are Automatically Repaired

Description: An interactive Web site exploring basic concepts of gene mutations through historical discovery

Labs & Experiments

How Regulatory Genes Direct Vertebrate Development

Description: Carefully timed gene signals are needed for fetal development. This advanced virtual laboratory experiment takes a close look at gene regulation in the pituitary gland of a human fetus.

Mystery Yeast Mutation (PDF 381.48 KB)

Description: In this inquiry-based exploration students are asked to discover the nature of the mutation in a yeast strain by designing and carrying out their own experiments. Students are provided with a conundrum: the same mutant yeast strain can grow on one type of media plate but not another.

The Ames Test

Description: An expert authored classroom laboratory experiment to assess how a chemical can cause changes to genetic material (DNA)

Teacher Resources

Monstrous Mutations Adaptation - Mutations and Variations Activity (PDF 605.24 KB, Lesson Plans/Lesson Activities)

Description: This hands-on activity is a simulation of how mutations can affect survival skills in animals. The objective of this activity is to understand and observe how mutations can be useful, harmful or neutral adaptations. Students will also observe how mutations have an affect on the organisms ability to survive.

The Chernobyl Disaster (Lesson Plans/Lesson Activities)

Description: Students explore how a nuclear accident can affect biological systems.