Investigating the role of mitochondrial membrane potential in paternal inheritance of mitochondria

Abstract

AbstractThe process of oxidative phosphorylation (OXPHOS) in mitochondria depends on an electrochemical gradient known as the mitochondrial membrane potential (Δψm). Reflecting high functionality, elevated Δψm usually depicts healthy mitochondria and contribute to organelle selection. This study investigates whether mitochondrial properties linked with bioenergetics, such as Δψm, may play a role in paternal inheritance of mitochondria. More specifically, how sperm Δψm responds to egg chemoattractants in bivalves characterized by distinct mitochondrial inheritance patterns: strict maternal inheritance (SMI) and doubly uniparental inheritance (DUI), the latter displaying sex-specific transmission of paternal mitochondrial DNA (mtDNA). Sperm Δψm was examined in four bivalve species:Mytilus edulisandRuditapes philippinarum(DUI), plusMercenaria mercenariaandMya arenaria(SMI). In absence of oocytes, sperm Δψm did not vary between the two groups. However, we revealed an increase in Δψm following egg detection only in sperm bearing paternally-derived mitochondria (DUI). This suggests, along with bioenergetic changes, that Δψm modulation might be a specific property of DUI paternal mitochondria, possibly implicated in their unique ability to be sex-specifically transmitted.