Environmental epigenetics investigates the cause-effect relationships between specific environmental factors and the subsequent epigenetic modifications promoting acclimatory responses in organisms. Given the dynamic and potentially heritable nature of different types of epigenetic marks, environmental epigenetics and its interaction with genetics constitute a promising venue for developing fast and sensible biomonitoring programs. Nevertheless, the lack of epigenetic knowledge in other ecologically and environmentally relevant organisms has hampered our understanding of these mechanisms in a broader range of ecosystems, most notably in aquatic environments. Fortunately, the growing availability of complete reference genome sequences along with the development of high-throughput DNA sequencing and bioinformatic methods are making the epigenetic study of non-model species (and more specifically marine and aquatic organisms) a reality. This session will include studies deepening our understanding of expression regulation in response to environmental cues, as well as studies using environmental epigenetic analyses for critical issues such as conservation and management of natural resources in marine and aquatic environments under global change impacts.
Developmental and Comparative Epigenetics
The structural and functional processes involved in gametogenesis, fertilization, and the subsequent transition from a zygote into a complex, multicellular adult organism are governed by an array of shared and specific cellular processes. Among them, a precise temporal and spatial pattern of structural changes in DNA organization and gene expression is fundamental to ensure normal development. Historically, it has been considered that the molecular mechanisms responsible for proper embryo development and cellular differentiation primarily rely on genetic factors. However, accumulating evidence has established a key role of the epigenetic mechanisms including DNA methylation, histone modifications, and non-coding RNA mediating gene silencing in these processes. While in mammals is well known that reprogramming of the epigenome is necessary to drive cellular differentiation and proper tissue specification, the nature of such a regulatory process and its underlying mechanisms are still unknown in other groups, notably in aquatic ecosystems, where embryos develop directly exposed to outer environmental parameters. This session will focus on epigenetic mechanisms and outcomes across ontogeny with implications for phenotypic plasticity and acclimatory success.
Epigenetics in Aquatic Resources Management
The application of epigenetics knowledge is now firmly established in biomedicine but is also gaining importance in ecology, evolution, and animal production. However, in contrast to livestock, fertilization and embryonic development is external and therefore easily influenced by the environment in the case of aquatic animals such as mollusks, crustaceans, and fish. Consequently, a big effort is being made toward integrating epigenetic programming to improve the production of aquaculture species. In addition, the expected higher variability of the epigenome (by comparison to the genome) is spawning new disciplines aiming toward a better understanding and management of exploited wild populations. Thus, epigenetics in aquatic resources management involves research on epigenetic diversity, the transmission of environmentally-induced epigenetic changes from parents to offspring, the identification of epialleles that are linked to a particular phenotype of interest, and the identification of epigenetic biomarkers to develop tools for improved management of aquatic resources. This session will address these topics with the ultimate aims of improving the domestication, reproductive capacity, nutrition, resistance to diseases, welfare, and phenotypic traits of interest of aquacultured species, and improving management practices of exploited and restored natural populations.
Genetics of Epigenetics: Heritability, Population Biology, and Evolutionary Dynamics
The unique feature that sets epigenetics apart from all other kinds of regulatory modifications is that the newly acquired changes can (potentially) be passed on to the subsequent generation(s), facilitating acclimatization and adaptation of the population and the species as a whole. However, direct evidence of this in the marine realm remains scarce or controversial, and the inter-generational dynamics (i.e genetics) of novel epigenetic marks remain largely unclear. This session will focus on the rates of appearance and loss of novel epigenetic marks in natural marine populations, their heritability, the role of natural selection in their spread, and emerging divergence patterns between populations and species reproducing sexually or asexually.