Transgenerational Epigenetic Instability as a Source of Novel Methylation Variants

Every cell that makes up an individual has the exact same genome and yet that individual is made up of a whole host of different cells. To achieve this variety of cell types, organisms utilize a variety of chemical modifications to DNA, which can be thought of as dials that selectively turn up or down how much of that gene’s product is produced. For example, some of the genes that are turned on in heart cells will not be turned on in liver cells and vice versa. Consequently, when a heart cell divides, it needs to send a signal to its daughter cells about which genes should be on and off. The term epigenetics is used to describe the inheritance of these kinds of non-genetic modifications. An open question is whether or not changes in these modifications can vary over time like mutations in DNA. Undoubtedly, if one picked any of these modifications and compared them across two individuals there would be many differences. What makes this problem challenging is disentangling those differences from genetic and environmental effects that could have also caused them. To overcome these challenges in an attempt to answer this fundamental question, we turned to the model plant Arabidopsis thaliana and DNA sequencing technology.