Identical twins share all 20,000 known genes and yet they may grow up to be physically different. If the sequence of their DNA is 100% same, why are the twins different? The short answer is: the twins may be exposed to diverse environmental factors over their lifetime; these environmental factors, such as food, exercise, bacteria in the gut or even the air we breath may have a big effect in our genes, turning them on or off. That applies not only to the twins, but also to your genes and mine.
Epigenetics is the study of how genes are switched “on” and “off”
Although identical genes carry the same sequence of DNA building blocks, the way they are being read differs. Ultimately, changing not only their expression, but also impacting the individual’s wellbeing and eventually changing health outcomes.
Our genes code for various proteins (enzymes) that carry out important functions in our bodies from your hair growth to how your liver metabolizes various foods or drinks. Epigenetics studies the biological processes that affect gene expression from when a fetus develops into a baby, child, adult and how the aging process evolves through changes in gene expression. Are you still with me? OK then. Our genes keep changing with age, they are never static from when you are born, our DNA is constantly being stimulated by the environment and lifestyle choices we make. So our gene function keeps changing throughout our life time. Although genetic expression is more stable as an adult, there are studies that show the reversibility of epigenetic changes.
For those who love to dive deeper into biochemistry and genetics, there are three systems studied in the last 30 years that are associated with initiating or silencing epigenetic changes which include DNA methylation, histone modification and mRNA expression. The most extensive studied subject has been DNA methylation and its association to related mutations such as cancers, immune dysfunctions, neuropsychiatric disorders and pediatric disorders.
Lifestyle and environmental factors influence epigenetic changes
Although there are numerous studies showing prenatal and early postnatal environmental factors show significant epigenetic influence, our lifestyle choices in adulthood also carry weight throughout our life and different environmental exposures can alter how our cells read our DNA.
What we eat to fuel our bodies and overall lifestyle influence the epigenetic tags and as a result our health outcomes. These lifestyle factors boil down to exercise, sleep, stress, behaviour, nutrition, alcohol consumption and tobacco smoking. Research evidence that these daily habits you deem healthy or not are actually making shifts in the way your DNA is expressed. Not only that, but the latest evidence shows your epigenetic changes are being inherited by your offspring. Mind blowing stuff to know your baby will be a creation of your lifestyle choices and behaviours. The way we age or keep young for a long time is influenced by our own behaviors.