What is the focus of the field of epigenetics?

The focus of the field of epigenetics is primarily on how environmental factors can influence gene expression without altering the underlying DNA sequence. This means that while the genetic code remains static, various external factors—such as diet, lifestyle, stress, and exposure to toxins—can lead to chemical modifications that affect how genes are turned on or off.

Epigenetics studies mechanisms such as DNA methylation and histone modification, which play crucial roles in regulating gene activity. These modifications can determine whether specific genes are expressed, and this has significant implications for development, health, and the manifestation of diseases. Thus, the exploration of how environmental factors shape genetic expression is central to understanding biological processes and the interaction between genes and the environment.

While the other options mention important aspects of genetics, they do not capture the essence of epigenetics. Changes to DNA sequences refer to mutations and genetic variations, repairing damaged DNA relates to cellular mechanisms that fix errors in the genetic code, and restoring normal gene expression involves aspects of genetic regulation but does not emphasize the environmental influences that characterize epigenetics.