Epigenetic regulation refers to the processes that influence gene activity without altering the underlying DNA sequence. This regulation can involve chemical modifications, such as the addition of methyl groups to DNA or changes to the histone proteins around which DNA is wrapped. These modifications can turn genes on or off, affecting how cells function and respond to their environment. Factors such as diet, stress, and toxins can impact epigenetic changes, leading to variations in gene expression. This means that identical twins, for example, may have different traits or health outcomes due to their unique experiences, even though they share the same genetic code.