Gene expression changes after parental exposure to metals in the sea urchin affect timing of genetic programme of embryo development.

It is widely accepted that phenotypic traits can be modulated at the epigenetic level so that some conditions can affect the progeny of exposed individuals. To assess if the exposure of adult ani-mals could result in effects on the offspring, the Mediterranean sea urchin and its well-characterized Gene Regulatory Networks (GRNs) was chosen as a model. Adult animals were exposed to known concentrations of zinc and cadmium (both individually and in combina-tion) for 10 days, and the resulting embryos were followed during the development. The oxidative stress occurring in parental gonads, embryo phenotypes and mortality, and the expression level of a set of selected genes, including members of the skeletogenic and endodermal GRNs, were evalu-ated. Increased oxidative stress at F0, high rates of developmental aberration with impaired gas-trulation, in association to deregulation of genes involved in skeletogenesis (dri, hex, sm50, p16, p19, msp130), endodermal specification (foxa, hox11/13b, wnt8) and epigenetic regulation (kat2A, hdac1, ehmt2, phf8 and UBE2a) occurred either at 24 and 48 h/pf. Results strongly indicate that exposure to environmental pollutants can affect not only directly challenged animals but also their progeny (at least F1), influencing optimal timing of genetic programme of embryo development, resulting in an overall impairment of developmental success.