The COVID-19 pandemic made one thing unmistakably clear: people can experience the same infection in dramatically different ways. Some develop mild symptoms, while others face severe illness. This wide range of outcomes raises a fundamental question. Why do two people exposed to the same pathogen respond so differently?
A major part of the answer lies in differences in genetics (the genes you inherit) and life experience (your environmental, infection, and vaccination history). These factors influence how cells behave through subtle chemical changes known as epigenetic modifications. These molecular changes help determine which genes are active or silent, shaping how cells function without altering the underlying DNA sequence.
Researchers at the Salk Institute have now created a detailed epigenetic catalog that shows…