Esdeveniments | 14 April 2023 | Friday talks

Understanding the adaptive role of epigenetics in naturally inbred fish



Epigenetic variation represents a potential mechanism to generate adaptive responses in the presence of low genetic diversity and could be an alternative source of adaptive plastic phenotypes which may explain the persistence of highly inbred populations in variable environments. Although epigenetic modifications can arise independently from variation in the underlying DNA sequence, the adaptive relevance of the epigenetic variation and its heritability is still unclear and seems to depend to some extent on genetic variation. To what extent epigenetic modifications act independently from genomic variation is key to understanding their potential role in evolution. Inbred organisms provide a uniquely opportunity to detangle genetic from epigenetic variation, but naturally inbred vertebrate models are difficult to find. Mangrove killifishes from the Kryptolebias genus are ideal for these studies. Kryptolebias marmoratus and K. hermaphroditus are the only two known self-fertilising vertebrates, consisting mainly of selfing hermaphrodites, with very few males and high homozygosity. We have used this genus to analyse the relationships among genetic and epigenetic (DNA methylation) variation, microbiome composition, behaviour and response to parasite loads (as proxies for fitness) in lab and wild populations. We found evidence that DNA methylation patterns depend on the dynamic interaction between the genotype and the environment but epigenetic diversity does not seem to be a substitute for genetic diversity in populations with low genetic variability. Yet, we also found epigenetic parental effects related to the rearing environment which, if maintained, could have long-term evolutionary and act as an evolutionary bet-hedging strategy for species with low genetic diversity under environmental change. Our results also indicate that the skin microbiome, together with host genetics and environment, are associated with the host methylation profile, highlighting the importance of considering the interaction between the microbiome and the host genome as a potential epigenetic mechanism (the holoepigenome) to understand host adaptation to environmental change.

Brief biography

Currently professor of evolutionary ecology at Swansea University. My work is primarily focused on conservation genetics, molecular ecology and resource management (fisheries and aquaculture), mainly but not exclusively, on aquatic organisms. Degree in Biology at the University of Oviedo and six years as a Scientific Advisor for the Cantabrian Government before being awarded a PhD in Conservation Genetics from the University of Cantabria. Then postdocs at the Institute of Zoology in London and the University of St Andrews before being a Lecturer at the University of Aberystwyth.