Epigenetics is a fascinating field of science. If you aren't familiar with it, the epigenome is the study of how your behaviors and environment impact gene expression. I pose the question to my students- if an identical twin gets cancer, does that mean the other twin will automatically get cancer? Students will generally say no. If that's the case, then what controls gene expression?
The cell membrane, which surrounds the cell, is covered in receptors. They act as antennae so cells can send signals and communicate with one another. Cells respond to environmental signals all the time- examples could include releasing insulin when blood sugar rises, or dividing when cells die and numbers drop. (Because of this, it could be argued that the cell membrane is the control center of the cell, not the nucleus. While the nucleus holds the genetic information that is needed to make proteins, it is the membrane that acts as the guy in charge by receiving signals on how to proceed).
So essentially you could have a gene for something, but unless the cell receives a signal to turn the gene on, (in other words- copy it and turn it into a protein), the gene will remain off. You could very easily have a cancer gene but live your life cancer free if that gene remains turned off. The decisions you make in your life, which influence cellular environmental factors, play a large role in gene expression. Here are some activities you could do with your students to teach them about epigenetics:
1. NASA Twin Study: You may have heard about Mark and Scott Kelly, who are identical twins and NASA astronauts. Both twins spent time on the International Space Station, but Scott spent a lot more time- a whole year. NASA compared Mark's DNA with Scott's DNA after he returned to Earth. This was a unique opportunity to learn the impact of space and zero gravity on our DNA and gene expression. You can learn more about the study here.
2. Case Study: University of Buffalo has a TON of case studies I encourage you to check out. (They are all free, but if you want the answer key there is a yearly subscription fee). One study is called "Identical twins, identical fates?" that explores epigenetics.
3. Learn Genetics: University of Utah's learn genetics website is an amazing resource for all things genetics. They have a section just on epigenetics. The "epigenome at a glance" is a great introductory video.
4. Partner Activity: This lesson and activity introduces students to epigenetics. Students will read about the agouti mice study (super fascinating!) and then complete a "twin" activity with a partner.
5. Bacteria Culture Lab: If you have time to order supplies, check out this lab from Flinn Scientific. Students will see the effect of temperature on bacteria growth and phenotype (it will change color). You will need to prepare agar slides and have access to an incubator.
6. Podcast: Big Biology podcast has an episode called "genes don't do crap" that features Dr. Massimo Pigliucci, an evolutionary biologist and philosopher. The episode is 16 minutes long, and I would recommend this for honors or AP students.
7. Queen Bee: Bees are a great example of epigenetics in action. The bees in an entire hive all have the exact same DNA- the drones, worker bees, and Queen are all clones. If they are all clones, then why do they look different and have different jobs? The answer is epigenetics and "royal jelly". Check out this video you can show students that explains more detail.
8. Documentary: The NOVA documentary "Ghost in your genes" investigates how our "secondary genome" helps determine our biological fates.
9. Epigenetics Game: This game has 4 levels students can work through all dealing with epigenetics.
10. Histone Model: In this download from University of Utah, you can have students build a paper histone model.