For decades, we believed our health, lifespan and disease risks were fixed at birth—sealed within the double helix of our DNA. Now, that idea has been overturned. The science of epigenetics—the study of how chemical ‘switches’ control gene activity—has reshaped how we and research scientists understand life. If the DNA helices are the hardware in us, then epigenetic switches are the software that control the hardware. This software influence shows that genes are not static codes, but dynamic instructions that respond to our environment, lifestyle and even our emotions. The epigenetic switches—similar to on/off switches—don’t rewrite the instructions in the DNA manual, but they control which parts are to be read and how much, as well as which are to be skipped for effective gene expressions.
So, our biology listens to the life we lead, the thoughts we harbour and the emotions we feel. The prefix ‘epi’ means ‘above’, so epigenetics refers to what happens above our genes. Chemical modifications that decide which genes are switched on or off are mostly: DNA methylation, histone modifications and chromatin remodelling. These affect how tightly the DNA is packed in the cell. When a gene region is tightly wrapped, it’s silent; when it’s open, it’s active. This control system shapes how cells work, how our body ages and even how our brain adapts to stress or trauma.
Think of your DNA as a library of books, each containing instructions for one body part—heart, skin, brain or immune system. But your body doesn’t read every book at once. The epigenetic switches act like bookmarks or sticky notes that tell the cell which pages and which part of the page to read and which to skip. These sticky notes change as life progresses, taking in its fold impacts of all the changes and events we go through. What you eat, how much you move, how you sleep, the air you breathe and even the thoughts you think—all can rewrite these molecular bookmarks. A poor diet or stress can blur or move them, silencing protective genes. Healthy living, meditation and prayer, on the other hand, can add new notes that activate genes promoting repair and resilience. In other words, healthy habits are molecular conversations with our genome to improve it for a better life experience. Our lifestyle, in a very real sense, writes notes on the margins of our DNA to shape our stories.
Remarkably, epigenetic switches can also be inherited and passed on to future generations. The lifestyle choices, mental stress and even the generational experience of famine/drought/social injustice, may influence not only our health, but that of our children and grandchildren, too.
Despite this progress in genetics, we must know that we are only beginning to understand the complexity of the epigenome—the collection of all the epigenetic marks on the DNA in a single cell. Its cell-specific patterns and constant environmental interplay make it one of biology’s most intricate systems.
The science of epigenetics can have a massive real-life impact on public health recommendations by confirming the molecular mechanism of environmental effects. For example, a mother's diet during pregnancy—like adequate folic acid/B vitamins—can impact the child's lifelong risk for diseases like heart disease and diabetes by influencing DNA methylation patterns in the foetus.
Even more exciting is the research area where scientists are learning to “reprogram” the epigenome. Studies show that epigenetic editing can slow biological ageing, repair damaged tissues and even treat/reverse cancer-related changes. There are FDA-approved drugs (histone methyltransferase inhibitors, DNA methyltransferase inhibitors, to name a few) that modify the chemical switches on DNA in patients to “reprogram” a cancerous cell back towards a more normal state or make it sensitive to other treatments.
The diseases that have shown proven clinical results through epigenetic interventions are myelodysplastic syndromes, types of leukaemia, T cell lymphomas and sarcomas.
As this field advances, we are stepping into a new era of medicine, where health and even destiny become choices we can shape. Epigenetics is finding intriguing parallels in ancient Indian philosophy. It shows that our inner and outer worlds continuously shape our biology. Indian spirituality has long held that consciousness governs matter.
The idea of karmic or Akashic records, which hold impressions of all thoughts and actions across lifetimes, finds a poetic mirror in the concept of epigenetic inheritance. Just as experiences can leave molecular imprints on genes passed to future generations, our spiritual traditions teach that karmic patterns influence the soul’s journey.
Empowered with the knowledge of epigenetics, we can now imagine a world where ageing is not inevitable, where cancer risk is reduced by restoring healthy gene function, and where mental wellbeing can be strengthened by nurturing our inner environment. Epigenetics is making this vision real. It shifts biology from being about fixed letters to being about annotations, edits and rewrites—a living script that evolves with every breath, meal and emotion. The epigenome is rewriting the story of life, and for the first time we understand that the pen is in our hands.
The writer is a pathologist and an author.