The (Dual) Origin of Epigenetics

Abstract

"Epigenetics" has different meanings for different scientists. Molecular biologists are probably most familiarwith a definition of epigenetics as "the study of mitotically and/or meiotically heritable changes in gene function that cannot be explained by changes in DNA sequence" (Riggs et al. 1996). For them, epigeneticmechanisms would include DNA methylation and histone modification. Functional morphologists, however,would be more familiar with a definition such as that ofHerring (1993), for whom epigenetics refers to "the entire series of interactions among cells and cell productswhich leads to morphogenesis and differentiation." Shecontinues that "among the numerous epigenetic factorsinfluencing the vertebrate face is mechanical loading"and that "epigenetic influences range from hormones andgrowth factors to ambient temperature and orientation ina gravitational field." In this note, I will argue that thesedisparate definitions have come about because "epigenetics" had at least two semi-independent origins during the20th century...