Mitochondrial genome inheritance and replacement in the human germline

Abstract

Mitochondria, the ubiquitous power packs in nearly every eukaryotic cell, contain their own DNA , known as mt DNA , which is inherited exclusively from the mother. The number of mitochondrial genomes varies depending on the cell's energy needs. The mature oocyte contains the highest number of mitochondria of any cell type, although there is little if any mt DNA replication after fertilization until the embryo implants. This has potential repercussions for mitochondrial replacement therapy ( MRT ; see description of currently employed methods below) used to prevent the transmission of mt DNA ‐based disorders. If only a few mitochondria with defective mt DNA are left in the embryo and undergo extensive replication, it might therefore thwart the purpose of MRT . In order to improve the safety and efficacy of this experimental therapy, we need a better understanding of how and which mt DNA is tagged for replication versus transcription after fertilization of the oocyte.