A concept that is strongly linked to the microbiome and its impact on the body, is epigenetics. As Dr Emma Beckett explains in this article, epigenetics is one way that the way we live our lives can be imprinted on the body, and passed down from one generation to the next. Effects of the microbiome on epigenetics may be another an important way that the microbiome affects our health. Over to you, Emma.
Every cell in the human body (excluding our microbes of course!) has the same DNA. Yet, we have different types of cells making our different tissues. From the same DNA we make skin cells, heart cells, immune cells, hair cells and so many more.
This is thanks to epigenetics - marks and modifications that include the instructions for which genes to switch on, and which to switch off. Epigenetic marks include DNA methylation (methyl groups added to DNA in the right spot switch genes off), histone modifications and chromatin remodelling (which change the way the DNA is wound and unwound to expose the genes). One analogy for epigenetics is an orchestra playing music. The notes are the genes, but the conductor and the musicians decide how fast and loud to play, which instruments are used, and how many.
For a lovely depiction of this orchestral analogy, see this video from Nature Videos.
Epigenetics doesn’t just allow for different cells to be made, it also allows adaption to environmental exposures (like sunlight, diet and pollution) and explains differences between identical twins. While our genes are fixed, our epigenomes can change. The way we live changes our epigenetics, meaning that our lifestyle is ‘remembered’ in the body. Diseased cells have different epigenetic marks to healthy cells. Targeting epigenetics is one way to treat disease into the future.
Epigenetic marks can be inherited – meaning they can be passed on when new cells are made. It is also believed that they can be passed down from parents to offspring. So, the environment of your parents, grandparents, and even great grandparents can change the markings on your genes. A powerful example of this is different patterns of DNA methylation differential methylation status observed in adults conceived during the Dutch famine of World War II, compared to their siblings conceived outside of famine. Exposure to the famine during early gestation was associated with higher rates of coronary heart disease, a more atherogenic lipid profile (more likely to clog the arteries), disturbed blood coagulation, and more obesity, compared to sibling who were born outside of the famine.
The word epigenetics was first coined in the 1940s, and literally means “above genetics.” But, we are still learning how epigenetics works and the consequences for health and disease. We know that epigenetic changes can occur in response to factors such as bodyweight, physical activity, diet, and environmental toxins, all of which are potentially controlled by our microbiomes. Bacterial metabolites in our gut microbiome could change our epigenomes and link our microbiota to health and disease. In the future this might be something we can target to prevent or cure diseases.
Dr Emma Beckett is a Post-Doctoral Research Fellow in the School of Medicine and Public Health at the University of Newcastle. She investigates gene-nutrient-environment interactions, and the consequences of these interactions for health and disease. She tweets about science, cats, soccer and baking @synapse101.
Image credits: Epigenetics by AJC1 is licensed under CC BY-NC-SA 2.0. Emma's portrait courtesy of Emma.