Estimated Lesson Duration:

45 minutes


Introduce students to epigenetics and how an individual’s genome responds to his or her environment.

Big Understanding: The epigenome is a set of chemical switches and markers that influence gene expression. Diet, environmental stressors, physical activity, and exposure to toxins can activate these chemical switches that regulate gene expression without changing the underline genetic code. Epigenetics is the study of changes in gene activity that do not involve changes to the genetic code.

Essential Questions: Identical twins are genetic carbon copies, meaning their DNA sequencing is the same. Yet physically they become increasingly different over time. Why is this so?

This lesson is geared to middle school, though it can easily be adapted for high school audiences

Key Concepts and Standards:

Key Concepts: Epigenetic, genome, markers, diet, environmental, DNA sequencing, physical activity, gene activity

Standards: Download the summary sheet about how this lesson meets standards

The standards listed were identified using key concepts from each individual lesson. These key concepts were aligned with the specific Oregon State Standards, Common Core Standards, and Next Generation Science Standards that apply specifically to each individual lesson.

Teachers may consult the Oregon Department of Education’s website for additional terms related to each lesson.


Preparations/ Materials

Materials: Teacher instruction and the student handout on “Diverging Twins”

Preparation: Listed below is basic background information on how diet, physical activity, and stress interact with the epigenome:

  • DIET – The nutrients the body extracts from food enter metabolic pathways where they are manipulated, modified and molded into molecules the body can use. One such pathway is responsible for making methyl groups – important epigenetic tags that silence genes.
  • STRESS – Chemicals released in the body in times of stress interact with the epigenome. Many studies are focusing on the effect of the stress hormone cortisol, and how it influences epigenetic tags and thus gene expression.
  • PHYSICAL ACTIVITY – While the overall effect of physical activity on the epigenome is not yet fully understood, there is evidence that hormones produced during physical activity may change epigenetic tags and thus gene expression.
  • EXPOSURE TO TOXINS – These are potentially harmful substances that include alcohol, smoking and exposure to pesticides, air pollutants, and harmful metals such as lead and nickel and can influence epigenetic tags and thus gene expression.


Downloadable Lesson and Supporting Materials

Lesson Plans