What does epigenetics study?

Epigenetics studies changes in gene expression that occur without alterations to the underlying DNA sequence. This field examines how various factors, such as environmental influences, lifestyle choices, and developmental stages, can cause modifications in gene expression through mechanisms like DNA methylation and histone modification. These changes can affect how genes are turned on or off, ultimately influencing an organism's phenotype without changing its genetic code.

Understanding epigenetics is essential because these changes can be reversible and may have implications for inheritance and disease. For instance, certain epigenetic modifications can be passed from one generation to the next, affecting traits and susceptibility to conditions without altering the actual DNA sequence itself. This contrasts with the other choices, which involve fundamental genetic processes such as mutations, DNA replication, or the inheritance of traits based solely on genetic factors.