Histone-mediated transgenerational epigenetics

Epigenetic mechanisms operate at the interface between the environment and genome, by converting the environmental stimuli to phenotypic responses through changes in the chromatin landscape, which ultimately affects gene expression in the absence of alterations in DNA sequence. In this scenario, transgenerational inheritance occurs when epigenetic variations induced by environmental stimuli are transmitted through the germ line to succeeding generations that had never experienced those stimuli. There is an ever-growing list of reports indicating that histones are fundamental players in these processes in a variety of organisms. In this chapter, we provide a perspective on histone-driven epigenetic mechanisms, such as histone posttranslational modifications, incorporation of histone variants, and nucleosome positioning, illustrating their interwoven hierarchies of activity and highlighting their roles in the transgenerational inheritance of genomic functions.