Can the epigenome change?

Yes, environmental factors such as physical activity, tobacco smoking, diet, obesity, stressors, and alcohol consumption can contribute to changing the epigenome. For example, diet can influence DNA methylation patterns, while stress hormones can affect histone modifications. Additionally, the epigenetic marks present at birth are not fixed and can undergo changes throughout childhood and adulthood. Specifically, the epigenome undergoes changes during different stages of development, including embryogenesis, fetal development, and aging. During development, epigenetics plays a vital role in determining the specialized functions of different cells in the body, such as whether a cell will become a heart cell or nerve cell despite having the same genetic information. As individuals age, changes in the epigenome occur as well. For example, it can alter DNA methylation patterns; one study showed that a newborn exhibit highest level of DNA methylation, while a 103-year-old individual showed the lowest level of DNA methylation and a 26 year old exhibit levels in between the two. Infections and germs have the ability to alter an individual's epigenetics in a way that compromises their immune system, thus aiding their own survival within the body. DNA methylation and histone modification are also key processes that lead to epigenetic changes in the genome. These changes accumulate over a person's lifetime and can be inherited by future generations.