The Role of Epigenetic Communication in the Co-regulation of Holobionts’ Biology: Interspecies Probabilistic Epigenesis

Current fast-paced advances in molecular biology, microbiology, and developmental biology mean a true revolution to how we see organism ecology and evolution. Microorganisms are conventionally regarded as a source of environmental influences capable of interacting with a wide variety of eukaryotic and prokaryotic hosts reciprocally impacting their phenotypic characteristics and generating ecological and evolutionary innovations. At the same time, it has been demonstrated the crucial role of epigenetic molecular mechanisms, such as DNA methylation, histone modifications, and RNA-related processes, in the execution of various house-keeping tasks in all kinds of organisms, overseeing the regulation of developmental plasticity, ontogenetic trajectories, and adaptations to the surrounding environment that define the traits used for categorizing life forms into discrete units we call species. In this context, it has been proposed that the development of symbiosis occurs through integrative and the coaction of interspecies epigenesis conforming ecologically and evolutionary symbiotic lifeforms known as holobiont. Strikingly, this process has been found to operate under the language of the different pre and posttranscriptional epigenetics allowing the reciprocal interaction between different regulatory layers that dynamically integrates into the holobiont’s plasticity and inheritance in an epigenetic fashion. Here, I present evidence found in varied holobiont systems demonstrating the pervasive role of epigenetics in symbiotic dynamics and the origin of eco-evo-devo novelty. Finally, I highlight the heuristic value of considering epigenetic molecular mechanisms as an additional regulatory dimension for developmental symbiosis under the light of Gottlieb’s Probabilistic Epigenesis, supporting the view of epigenetic molecular mechanisms as the communicating language of symbiotic interactions.