Biology subjects

Clavereau, I.

Publications and source records attributed to Clavereau, I..

3 recordsLinked to original sources

bioRxiv2026

Animal retrozymes are nonautonomous sequences of Penelope-like elements

Hammerhead ribozymes (HHRs) are small catalytic RNAs found across diverse life forms. In animal genomes, they can be encoded by genes organised in dispersed copies or in tandem genomic arrangements. These tandemly organised forms, known as Non-LTR retrozymes, were recently identified as a distinct group of non- autonomous retrotransposons, likely mobilised via a rolling-circle transposition mechanism and potentially involved in host transcriptome regulation. However, their evolutionary origins remain poorly understood. Here, we investigate the presence, genomic distribution, and possible origins of Non-LTR retrozymes across a broad range of vertebrate species. We find that these elements display a patchy phylogenetic distribution, notably absent from the Aves and Mammalia lineages. In species where they are present, retrozyme copy number, consensus length, and monomer proportion vary widely across species and retrozyme families, suggesting diverse amplification dynamics. Genomic mapping reveals a significant enrichment of Non-LTR retrozymes in intergenic regions and their exclusion from introns and exons, indicating selective pressure against genic insertion. Strikingly, the phylogenetic distribution of Non-LTR retrozymes coincides with that of Penelope-like elements (PLEs). Phylogenetic analysis further shows that the pLTR region of PLEs is closely related to Non-LTR retrozymes, supporting the hypothesis that Non-LTR retrozymes are non-autonomous derivatives of PLEs. Together, our findings shed new light on the evolutionary origin and genomic behaviour of Non-LTR retrozymes and underscore their potential regulatory roles in vertebrate genomes.

genomics↗

bioRxiv2023

Maternal body condition affects the response of the gut microbiome to a widespread contaminant in larval spined toads

Glyphosates primary metabolite, aminomethylphosphonic acid (AMPA), is the most detected pollutant in surface waters. Recent studies have raised concerns about its toxicity, yet underlying mechanisms remain poorly understood. A disruption of the gut microbiome, which plays a crucial role in host health, could mediate most of the adverse effects. We investigated the impact of AMPA exposure on the gut microbiome of spined toad tadpoles (Bufo spinosus). We hypothesized that AMPA could alter the gut microbiota composition and that these effects could depend on the microbiota source. We exposed tadpoles to minute concentrations of AMPA and analyzed their faecal microbiota using 16S rRNA gene sequencing as a proxy of the gut microbiota. AMPA exposure decreased the gut bacterial biomass and affected the bacterial community composition of tadpoles faeces. Furthermore, we observed interactions between AMPA exposure and maternal body condition on the Bacteroidota and Actinobacteriota phyla abundances. This suggests a maternal effect on early-life microbial colonizers that could influence the response of the gut microbiome to AMPA. These findings highlight the importance of considering the gut microbiome when studying the effects of environmental contaminants. Further research is needed to elucidate the long-term implications of this microbiome alteration for amphibian health.

ecology↗

bioRxiv2020

Insights on the evolution of vertebrate microbiomes from the analysis of the Xenopus frog microbiota across life stages

BackgroundThe microorganism world living in amphibians is still largely under-represented and under-studied in the literature. Among anuran amphibians, African clawed frogs of the Xenopus genus stand as well-characterized models with an in-depth knowledge of their developmental biological processes including their metamorphosis. In this study, we analyzed the succession of microbial communities and their activities across diverse body habitats of Xenopus tropicalis using different approaches including flow cytometry and 16s rDNA gene metabarcoding. We also evaluated the metabolic capacity of the premetamorphic tadpoles gut microbiome using metagenomic and metatranscriptomic sequencing. ResultsWe analyzed the bacterial components of the Xenopus gut microbiota, the adult gut biogeography, the succession of communities during ontogeny, the impact of the alimentation in shaping the tadpoles gut bacterial communities and the transmission of skin and fecal bacteria to the eggs. We also identified the most active gut bacteria and their metabolic contribution to tadpole physiology including carbohydrate breakdown, nitrogen recycling, essential amino-acids and vitamin biosynthesis. ConclusionsWe present a comprehensive new microbiome dataset of a laboratory amphibian model. Our data provide evidences that studies on the Xenopus tadpole model can shed light on the interactions between a vertebrate host and its microbiome. We interpret our findings in light of bile acids being key molecular components regulating the gut microbiome composition during amphibian development and metamorphosis. Further studies into the metabolic interactions between amphibian tadpoles and their microbiota during early development and metamorphosis should provide useful information on the evolution of host-microbiota interactions in vertebrates. This article has been peer-reviewed and recommended by Peer Community in Genomics https://doi.org/10.24072/pci.genomics.100005

genomics↗