Heredity and biogenesis of mitochondria: evolutionary and functional aspects.

Nearly all animal species inherit mitochondrial DNA in a matrilineal way: the mtDNA of the progeny originates entirely from the oocyte, whereas paternal mtDNA carried by spermatozoa is actively degraded pre- or post-fertilization by a variety of means. This well-known pattern goes by the name of “strictly maternal inheritance” of mitochondria or SMI. It is not currently known why SMI is so prevalent and what evolutionary advantage it confers exactly. Some bivalve species present a different mitochondrial inheritance pattern called doubly uniparental inheritance or DUI, the only known stable exception to SMI. Despite constituting an excellent system to study mitochondrial evolution and inheritance, its molecular background is poorly understood and the evolutionary equilibria it participates to even less so. The present thesis aims at uncover some of the molecular basis for DUI in R. philippinarum (Bivalvia, Veneridae) and to map some features of its basic biology.