Understanding natural epigenetic variation (original) (raw)

Recently, there has been increased interest in understanding the role of epigenetic processes in ecology and evolution. We now know that some epigenetic marks are not reset each generation, but are faithfully transmitted across generations, natural variation can exist not only at the DNA sequence but also epigenetic level, and that epigenetic variation alone can cause significant heritable variation in phenotypic traits. Moreover, heritable epigenetic modifications can be triggered by exposure to different environmental conditions. If we put these different pieces of evidence together, then this clearly suggests that epigenetic mechanisms could add an additional layer of complexity to heritable phenotypic variation, and thus to the diversity and evolutionary potential of natural populations. However, in spite of abundant speculation about the potential ecological and evolutionary implications of epigenetic processes, most previous work has been done on very few agricultural crops and model species such as Arabidopsis thaliana, frequently under artificial conditions, and we therefore still have no idea of the true importance of epigenetic processes in natural populations. Because of that, several authors have argued for expanding research efforts into ecologically relevant circumstances across model and non-model organisms and outlined experimental and statistical approaches that would facilitate the merging of molecular based insight with sound evolutionary ecology. Herrera & Bazaga (2010) provide an intriguing example of how researchers are now beginning to respond to this call.