Thermal transgenerational and rearing density effects in laboratory strains of zebrafish (Danio rerio)

EPICONCEPT Workshop 2015 Periconception Environment, Epigenetics and Periconception Environment, 26-29 April 2015, Dubrovnik, Croatia.-- 1 pageThere are species of fish in which sex determination is genetic, whereas in others is based on an interaction between genetic and environmental factors. Several studies have shown that environmental factors such as temperature and rearing density are able to affect adult se ratios, especially if animals have been exposed during early development. Furthermore, it has been described that temperature is capable of modulating the methylation levels of many genes involved in sex differentiation. Thus, there is evidence of the involvement of epigenetic regulatory mechanisms in the integration of environmental effects to modulate sex ratios in fish. Here, we used laboratory strains of zebrafish, in which sex determination mimics a polygenic system due to the loss of the major component of its genetic sex determination system due to the process of domestication. We used these fish to explore both the involvement of epigenetic mechanisms and transgenerational effects in the long-term modulation of gene expression patterns due to early exposure to either elevated temperature or rearing density. The studied endpoints, which were affected by these treatments, included not only population sex ratios but also genes involved in the stress response (i.e., cortisol synthesis and signalling), DNA methylation (i.e., different dnmts) and gonadal sex differentiation (i.e., different transcription factors and steroidogenic enzymes). Together, these studies contribute to our understanding of the importance of epigenetic regulatory elements during early environment in the establishment of the adult phenotypeSupported by MINECO grant AGL2013-41047-R “Epifarm” to FPPeer Reviewe