Mitochondria are sub-cellular organelles responsible for producing the majority of cellular energy
through the process of oxidative phosphorylation (OXPHOS), and are found in nearly all eukaryotic cells.
Mitochondria have a unique genetic system, mitochondrial DNA (mtDNA), which is a small, self-replicating and
diverse genome. In the past 30 years, mtDNA has made significant contribution to molecular ecology and
phylogeography. Mitochondria also represent a unique system of mitochondrial–nuclear genomic cooperation.
Additionally, mitochondrial dysfunction can be fatal. In this paper, we review several aspects of mitochondria,
including evolution and the origin of mitochondria, energy supply and the central role of mitochondria in
apoptosis, and mitochondrial dysfunction. It is shown that mitochondria play a critical role in many aspects of