The Human Genome Project, declared complete in 2003, elucidated the sequence of our genome. Researchers are now learning that another level of information—the epigenome— controls gene expression in part by controlling access to DNA. The gene-reading machinery is blocked when methyl molecules bind to DNA or histones. Conversely, when acetyl molecules bind to histones, DNA becomes less tightly wound and genes become available for transcription. The pattern of these chemical tags can be copied across cell divisions and may even be passed on to an
individual’s offspring. However, because acetylation and methylation are driven by cell signals, the epigenome is dynamic, enabling it to respond to the environment. Thus, epigenetic tags in a cell lineage can change over the course of an individual’s lifetime, even leading to differences between
identical twins. This feature focuses on multimedia resources that can be used in teaching epigenetics at the undergraduate and secondary level; several hands-on activities also are included.