Mitochondrial transmission

There is only one exception to the strictly maternal mode of inheritance of mitochondrial DNA (mtDNA) in animal species. Indeed, some bivalves have a radically different mode of mtDNA transmission named “Doubly uniparental Inheritance” or DUI. The species with this unique system are characterized by the presence of two distinct mtDNAs: one that is passed maternally to females and males (F mtDNA), and the other paternally transmitted M mtDNA to males only. My research aims to elucidate the molecular mechanisms underlying this unusual system of mitochondrial transmission.

Comparative mitogenomics and new mitochondrial genes

Why some groups of organisms are relatively conservative in terms of their mt genome content and organization while others exhibit an astonishing diversity in mt chromosome form and number as well as coding content and organization? My team is interested in understanding the genetic, life history, and ecological factors that contribute to the evolutionary dynamics of mitochondrial genomes in animals. Also, since the publication of the first complete sequence of human mtDNA in 1981, the molecule is described, in the vast majority of animal species, as coding for 13 proteins involved in energy production by mitochondria. However, our work has shown that we have underestimated the coding and functional capacity of mitochondrial DNA. We seek to better define the functions of these new genes.

Mito-nuclear interactions and co-adaptation

Bivalve species with their atypical system of doubly uniparental inheritance of mtDNA are characterized by the presence of two highly divergent mtDNAs (20-40% divergence) within the same male individual. In humans, one mutation in the mtDNA (<0.0001% divergence) can result in pathological situations. How and why such a radically different system is maintained in bivalves? My research aims to better understand the interactions and co-adaptation among the 3 genomes in bivalves with DUI.  

Physiological adaptations of animals to environmental constraints

Mitochondria and their genomes have recently been identified as a key factor in the adaptation of organisms to climate change, and a model for the study of speciation. My team is particularly interested in investigating the role of mitochondria and their genomes in adaptation and speciation. We use an integrative approach which evaluates, among other, the link between the mitochondrial genotype and the phenotype.

Sex-determining mechanisms

Our team found that the unusual system of doubly uniparental inheritance of mtDNA may be involved in sex determination, thus making bivalves the only group of animals with a sex determination system that directly involve mitochondria, but this remains to be fully demonstrated. Part of my research is to demystify the underlying mechanisms for DUI and sex determination in bivalves.

Mitochondrial epigenetics

Epigenetic mechanisms (e.g. DNA methylation), which modulate gene expression in response to environmental stimuli, are key elements in the regulation of mito-nuclear interactions. For example, mtDNA variants will influence the expression of nuclear genes and their level of methylation. Moreover, as the nuclear DNA, the mtDNA is also subject to epigenetic modifications. We study these mitochondrial and nuclear epigenetic modifications in animals.