Selective breeding of the major commercial fish species is essential to ensure sustainability of the rapidly expanding aquaculture sector, which is a major source of animal protein worldwide. The current molecular approaches used for selection of desired traits in farmed fishes are mainly based on genetic markers and genomic selection without considering the impact of epigenetics. However, epigenetic mechanisms are emerging as a new source of phenotypic variability and plasticity in response to environmental cues. We have recently discovered that changes in microRNA (miRNA) expression levels and DNA methylation (5mC) and hydroxymethylation (5hmC) occur during Nile tilapia domestication. EPIMARK has shown that a subset of these miRNAs and 5mC/ 5hmC marks can be used to distinguish between fish with slow- and high growth rates. Selecting for fast-growing fish will reduce the time required to reach market size and the associated maintenance costs, ultimately yielding a more profitable and sustainable business. EPIMARK has also developed molecular tests based on real-time PCR to identify and quantify target miRNAs and 5mC/ 5hmC marks. We are in the process of patenting the use of a panel of epigenetic markers of growth in fish breeding programmes. Our commercial feasibility analysis demonstrated that EPIMARK has clear economic potential in a rapidly growing market but the technology needs further maturation. Hence, the most appropriate route to market at this stage is collaborative research with an industrial partner. Broadening the scope of EPIMARK’s epigenetic markers to other commercially lucrative farmed species and integrating these with current state-of-the-art genetic markers would substantially enhance EPIMARK’s competitive edge by permitting a complete, unprecedented (epi)genomic overview of commercially relevant traits, establishing a new paradigm within the aquaculture field.
