EMERGE - Environment, (epi)genoMEs, deteRminisms and ontoGEnesis

General topics

The team brings together colleagues from the unit specialized in ontogenesis processes, which are the processes that lead to the establishment of differentiated cells, tissues, organs or functional structures. These processes can occur during the development phases (embryo, larvae) as well as during the juveniles or adult phases: embryogenesis, morphogenesis, gametogenesis, gonadogenesis, neurogenesis and genesis of the shell (biomineralization). All these processes condition closely the adaptation of organisms to their environment and if their determinism is primarily genetic they are also likely influenced by their environment.

Members of the team develop their expertise on economically important species presenting relevant characteristics for the questions addressed: the differently structured germinal niches between oysters (Mollusc, bivalve) and the small-spotted catshark (Vertebrate, Chondrichthyes), gametogenesis blockings observed in triploid oysters with partial sterilisation, the particularly structured and developed nervous system of the common cuttlefish (Mollusc, Cephalopod) or even the biomineralization of ormers nacre (Mollusc, Gastropod). These species are located at key positions on the phylogeny, permitting the evolution history of ontogenesis processes studied to be adressed.

Questions adressed are the following:

>What are the cellular and molecular mechanism involved in the different ontogenesis processes studied?

>Does the environment impact these mechanisms and how?

The team’s researchers and engineers have an expertise in complementary approaches to address these different questions: chromosomic, genetic and epigenetic studies (qPCR, Next Generation Sequencing and bioinformatic, immunoprecipitation, karyotypes), cellular and histological studies (cellular cultures and sorting, qualitative and quantitative microscopy), molecular characterisation (immunolabeling, hybridisation), in vivo and in vitro functional tests (exposition, injections, transplantation, genome editing), experiments in controlled environments, fieldwork…

Research axis

Axis 1: Molecular and cellular determinism of the studied ontogenesis processes

This axis decrypts the cellular and molecular pathways involved in the fate of cells engaged in the ontogenesis processes. Identity factors of stem cells (germinal, neural, somatic), factors participating in the different differentiation pathways possible (in gametes, neurons, supporting cells) or in the maintenance or even the blocking of their pluripotency state and factors driving the structures establishment and functioning (histogenesis and organogenesis, hormones, enzymes, neurotransmitters,…) will be studied more particularly.

Axis 2: Influence of environmental conditions on ontogenesis processes

The environmental impact can be particularly determining for the sexual determinism, in the gametogenesis initiation, the reproduction effort or the embryonic and larval development. Similarly, the nervous structure maturation is influenced by external stimuli and a process like shell mineralisation is necessarily dependent on the mineral availability in the environment. In the context of global changes, the environment can also be a disrupting source for ontogenesis: what is the impact of ocean acidification or temperature rising no shell development and morphogenesis? In which ways the changes in abiotic and biotic parameters can interfere in sexual maturation, sex ratios, cellular fate? What are the ontogenesis processes adaptation capacities or resilience?

Axis 3: Epigenetic and ontogenesis

Indirect interactions exist between the environment and ontogenesis processes: via epigenetic mechanisms, the environment can modify and regulate genomes and transcriptomes and also imprint marks which will potentially be passed on from generation to generation. The oyster in particular, through its early development and reproduction control and its vulnerability to abiotic and biotic parameters, emerges as a lophotrochozoan model in this area.

Latest scientific articles

2020

2019

2018

Gallery

ILL EMERGE Embryon de petite roussette - A. Gautier
Comparaison des minéralisations de juvéniles d’Haliotis tuberculata entre pH 8 (A,C) et pH 7.6 (B,D)(from Auzoux-Bordenave et al.)  S. Auzoux-Bordenave
Embryon de petite roussette, Scyliorhinus canicula". Photo Aude Gautier
Les méthylomes développementaux de l'huître sont spécifiques du stade de développement et de type d'élément génétique considéré et soulignent la segmentation et la métamorphose - G. Rivière
Mise en place des ébauches gonadiques chez l'embryon de petite roussette - A. Gautier
Un inhibiteur d'ADN méthyltransférases altère le niveau et la localisation de la méthylation de l'ADN dans les embryons d'huître - G. Rivière
Chez Crassostrea gigas, méthylation de l’ADN et niveaux d’expression sont correlés au cours du développement (from Riviere et al. 2017) - G. Rivière