Project description:The domestication is an evolutionary process during which individuals will progressively adapt to an environment controlled by humans. It is accompanied by epigenetic and genetic modifications potentially leading to modifications in the transcriptomic profile in various tissues. The reproduction process is among the biological functions highly affected whatever the species and/or the way of domestication. Indeed, the reproduction success often decreases in domesticated populations. For fish, the molecular content of the eggs is crucial for the proper embryogenesis. Among these molecules the mRNA content depends directly from the gene expression and thus may reflect the genetic modifications occurring during this process. Here, we investigated the transcriptomic profile of eggs coming from females of two populations (F1 and Fx) that were reared in the same conditions and were genetically close. Our main goal was thus to determine how the domestication process may affect the reproduction success in the Eurasian perch and if it was mediated by the regulation of the transcription in the eggs. A regular follow up of the oogenesis progression showed few differences of the hormonal production between the two populations. Nevertheless, the histological study showed that the F1 females were more developed by the end of the oogenesis induction than the domesticated ones and as a result, they spawned earlier than the domesticated ones. The study of the early developmental success revealed significant differences between the populations. The microarray analysis of unfertilized eggs presented more than 350 transcripts differently expressed between the two populations. Among them, some specific genes were drastically more expressed in the domesticated (mex3B, hace1 and an uncharacterized protein) or F1 (per) populations. Our data show that the F1 population is more sensitive to the environmental conditions to advance oogenesis and reach the spawning season earlier. The transcriptomic profiles in eggs coming from the two populations were different and may lead to developmental impairments having a potential link with the domestication process. Further analyses are needed to explain these differences.
Project description:Determining the physiological effects of parasites and characterizing genes involved in host responses to infections are essential to improving our understanding of host-parasite interactions and their ecological and evolutionary consequences. This task, however, is complicated by high diversity and complex life histories of many parasite species. The use of transcriptomics in the context of wild-caught specimens can help ameliorate this by providing both qualitative and quantitative information on gene expression patterns in response to parasites in specific host organs and tissues. Here, we evaluated the physiological impact of the widespread parasite, the pike tapeworm (Triaenophorus nodulosus), on its second intermediate host, the Eurasian perch (Perca fluviatilis).
Project description:This study sought to evaluate the effects of dietary MeHg exposure on adult female yellow perch (Perca flavescens) and zebrafish (Danio rerio) reproduction by relating controlled exposures with subsequent reproductive effects. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, and the use of zebrafish allowed for a detailed analysis of the molecular effects of MeHg. MeHg exposures at environmentally relevant levels were done in zebrafish for a full life cycle, mimicking a realistic exposure scenario, and in adult yellow perch for twenty weeks, capturing early seasonal ovarian development. In zebrafish, several genes involved in reproductive processes were shown to be dysregulated by RNA-seq and QPCR, but no significant phenotypic or physiological changes were observed with ovarian staging, fecundity, or embryo mortality. Yellow perch did not appear to be affected by MeHg, either at a molecular level, as assessed by QPCR of eight genes in the pituitary, liver, and ovary tissue, or a physiological level, as seen with ovarian somatic index, circulating estradiol, and ovarian staging. Lack of impact in yellow perch limits the usefulness of zebrafish as a model and suggests that the reproductive sensitivity to environmentally relevant levels of MeHg differs between yellow perch and zebrafish.