A cell’s mitochondria, which resemble tiny organs, serve as its power source. They specifically create ATP, or adenosine triphosphate, a chemical that transports energy. The energy that eggs and embryos require to operate properly is produced by mitochondria, which can only be inherited from the mother’s egg. In order to supply energy to the embryo and control its environment, mitochondria go through structural and morphological changes during the early stages of an embryo’s growth. These activities are crucial to an embryo’s development before implantation within the womb.
The quality of a woman’s eggs declines with age. Because mitochondria have DNA, just like the nucleus of a cell, alterations or damage to the mitochondrial DNA as maternal age rises can cause mitochondrial malfunction. If the mitochondrial DNA is harmed, this can lead to insufficient ATP production or energy as well as the loss of other crucial mitochondrial processes that are necessary after fertilization. Low levels of mitochondrial DNA are also linked to improper embryo development and ineffective fertilization. Basically, developmental activities stop in an egg or embryo if there is insufficient energy available.
The embryo’s genome is active during days two and three of development, or from the four-cell to the eight-cell stage. The genetic material (chromosomes containing DNA) found inside a cell is referred to as its genome. When an embryo’s genome is turned on, it no longer needs the egg to grow; instead, it employs the cellular machinery inside of itself. The activity of the embryonic genome changes and this change is controlled by unique products made by the mitochondria. In about 10% of embryos, the transition from maternal egg control to embryonic genome control is not successful. This indicates that if the genome switch does not take place, an embryo that is on day two and at the four-cell stage may not develop further.