Biology subjects

Auffret, P.

Publications and source records attributed to Auffret, P..

4 recordsLinked to original sources

bioRxiv2026

Decoupling epigenetic variation from genetic variation reveals complementary dimensions of coral eco-evolutionary dynamics

Understanding how intraspecific diversity is structured is essential for predicting the eco-evolutionary trajectories of populations, especially under rapid environmental change. While such diversity has been extensively studied from a genetic perspective, much less is known about the distribution and ecological relevance of epigenetic variation within natural populations. To address this question, we focused on two species of reef-building corals belonging to distinct functional groups, Pocillopora acuta and Acropora hyacinthus, sampled across the South Pacific (New Caledonia, Fiji, French Polynesia). Using genome-wide Enzyme-Methyl sequencing, we jointly analyzed genetic (SNPs) and DNA methylation (CpGs) variation, while explicitly disentangling genetically associated from genetically independent epigenetic variation. Genetic and epigenetic structure showed contrasting spatial patterns, reflecting distinct temporal and ecological components of population dynamics. Genetic structure was strongest between archipelagos and followed an isolation-by-distance pattern consistent with long-term evolutionary processes. In contrast, epigenetic variation converged between colonies from different archipelagos. At finer spatial scales within archipelago, genetically independent epigenetic variation exhibited stronger structure than both genetic and genetically associated epigenetic variation, likely reflecting local environmental conditions. Together, our results show that genetic and epigenetic variation provide complementary insights into the eco-evolutionary processes shaping intraspecific diversity.

evolutionary biology↗

bioRxiv2023

The FIGNL1-FIRRM complex is required to complete meiotic recombination in the mouse and prevents massive DNA damage-independent RAD51 and DMC1 loading

During meiosis, nucleoprotein filaments of the strand exchange proteins RAD51 and DMC1 are crucial for repairing SPO11-generated DNA double-strand breaks (DSBs) by homologous recombination (HR). A balanced activity of positive and negative RAD51/DMC1 regulators ensures proper recombination. Fidgetin-like 1 (FIGNL1) was previously shown to negatively regulate RAD51 in human cells. However, FIGNL1s role during meiotic recombination in mammals remains unknown. Here, we deciphered the meiotic functions of FIGNL1 and FIGNL1 Interacting Regulator of Recombination and Mitosis (FIRRM) using male germline-specific conditional knock-out (cKO) mouse models. Both FIGNL1 and FIRRM are required for completing meiotic prophase in mouse spermatocytes. Despite efficient recruitment of DMC1 on ssDNA at meiotic DSB hotspots, the formation of late recombination intermediates is defective in Firrm cKO and Fignl1 cKO spermatocytes. Moreover, the FIGNL1-FIRRM complex limits RAD51 and DMC1 accumulation on intact chromatin, independently from the formation of SPO11-catalyzed DSBs. Purified human FIGNL1{Delta}N alters the RAD51/DMC1 nucleoprotein filament structure and inhibits strand invasion in vitro. Thus, this complex might regulate RAD51 and DMC1 association at sites of meiotic DSBs to promote proficient strand invasion and processing of recombination intermediates.

genetics↗

bioRxiv2020

Dual RNAseq highlights the kinetics of skin microbiome and fish host responsiveness to bacterial infection

a) BackgroundTenacibaculum maritimum is a worldwide-distributed fish pathogen known for causing dramatic damages on a broad range of wild and farmed marine fish populations. Recently sequenced genome of T. maritimum strain NCIMB 2154T provided unprecedented information on the possible molecular mechanisms involved in virulence for this species. However, little is known on the dynamic on the infection in vivo, and information are lacking on both the intrinsic host response (gene expression) and its associated microbiome community. Here, we applied complementary omic approaches, including dual RNAseq and 16S rRNA gene metabarcoding sequencing using Nanopore and short-reads Illumina technologies to unravel the host-pathogens interplay in experimental infection system using the tropical fish Platax orbicularis as model. b) ResultsWe show that T. maritimum transcriptomic landscape during infection is characterized by an enhancement of antibiotic catalytic and glucan catalytic functions while decreasing specific sulphate assimilation process, compared to in vitro cultures. Simultaneously, fish host display a large palette of immune effectors, notably involving innate response and triggering acute inflammatory response. In addition, results suggest that fish activate adaptive immune response visible through stimulation of T-helper cells, Th17, with congruent reduction of Th2 and T-regulatory cells. Fish were however largely sensitive to infection, and less than 25% of them survived after 96hpi. These surviving fish showed no evidence of stress (cortisol levels) as well as no significant difference in microbiome diversity compared to control at the same sampling time. The presence of Tenacibaculum in resistant fish skin and the total absence of any skin lesion suggest that these fish did not escape contact with the pathogen but rather prevent the pathogen entry. In these individuals we detected the up-regulation of specific immune-related genes differentiating resistant from control at 96hpi, which suggests a possible genomic basis of resistance while no genetic variations in coding regions was reported. c) ConclusionHere we refine the interplay between common fish pathogens and host immune response during experimental infection. We further highlight key actors of defense response, pathogenicity and possible genomic bases of resistance to T. maritimum.

genomics↗

bioRxiv2018

Whole transcriptome sequencing and biomineralization gene architecture associated with cultured pearl quality traits in the pearl oyster, Pinctada margaritifera

BackgroundCultured pearls are unique gems produced by living organisms, mainly molluscs of the Pinctada genus, through the biomineralization properties of pearl sac tissue. Improvement of P. margaritifera pearl quality is one of the biggest challenges that Polynesian research has faced to date. To achieve this goal, a better understanding of the complex mechanisms related to nacre and pearl formation is essential and can now be approached through the use of massive parallel sequencing technologies. The aim of this study was to use RNA-seq to compare whole transcriptome expression of pearl sacs that had producing pearls with high and low quality. For this purpose, a comprehensive reference transcriptome of P. margaritifera was built based on multi-tissue sampling (mantle, gonad, whole animal), including different living stages (juvenile, adults) and phenotypes (colour morphotypes, sex).\n\nResultsStrikingly, few genes were found to be up-regulated for high quality pearls (n = 16) compared to the up-regulated genes in low quality pearls (n = 246). Biomineralization genes up-regulated in low quality pearls were specific to prismatic and prism-nacre layers. Alternative splicing was further identified in several key biomineralization genes based on a recent P. margaritifera draft genome.\n\nConclusionThis study lifts the veil on the multi-level regulation of biomineralization genes associated with pearl quality determination.

molecular biology↗