Keeping mtDNA in Shape between Generations
Figure 2
The life cycle of mtDNA within the female germline of mice.
The total amount of mtDNA remains unchanged from the oocyte to the blastocyst stage, resulting in a dilution of the number of mtDNA molecules per cell with each cell division. Re-initiation of mtDNA replication does not occur until the postimplantation stage. At approximately E7.5, a physical bottleneck with a very low number of mtDNA molecules per cell has been reported, and thereafter replication reinitiates to increase the mtDNA content of the embryo. During the late stages of embryonic life and early postnatal life, oocytes are lost due to atresia.