Ariane Pouliot-Drouin
Project
Study of a natural heteroplasmy system to better understand its impact on mitochondrial functions.As a general rule, animal mitochondria (the powerhouse of cells) and their genome (mitochondrial DNA or mtDNA) are strictly maternally inherited. Thus, all cells have identical mtDNA molecules. This ensures compatibility of mitochondrial and nuclear genomes for proper bioenergetic efficiency. The presence of more than one type of mtDNA in cells, a situation called "heteroplasmy", can lead to mitonuclear incompatibilities. This phenomenon is associated with several human diseases. However, a naturally heteroplasmic system exists in some bivalve species by a doubly uniparental transmission (DUI) of mtDNA, where maternal mtDNA (F mtDNA) and paternal mtDNA (M mtDNA) are, respectively, transmitted by eggs and spermatozoa to embryos. However, only male individuals retain the M mtDNA in their gonads, specifically in their spermatozoa. Males are therefore heteroplasmic, as they possess two types of mtDNA (which are extremely genetically divergent) unlike females who are usually homoplasmic for F mtDNA. This could possibly affect the bioenergetic efficiency of cells, at least that is our hypothesis. This research project therefore seeks to link the level of somatic tissue heteroplasmy to mitochondrial enzymatic activities in order to have a more informed look on the impact of mitochondrial heteroplasmy in a naturally heteroplasmic animal model.
