The role of mitochondria in the establishment of oocyte functional competence.

Mitochondria are maternally inherited, semi-autonomous organelles with their own genomes (mtDNA), largely responsible for the generation of energy in the form of cellular ATP. However, mitochondrial replication and transcription of mtDNA do not commence until well into embryonic differentiation. This means that the oocyte needs to contain sufficient stocks of functioning mitochondria to fuel the first few days of embryonic development. In this review, I examine how qualitative and quantitative aspects of mitochondria help us define the notion of functional competence.