Mitochondrial DNA

Abstract

Mitochondria and chloroplasts are the only organelles with separate extranuclear DNA. According to the endosymbiotic theory, mitochondria used to be prokaryotes, and so, mitochondrial DNA shares several characteristics with prokaryotic genomes. The circular human mitochondrial DNA contains 37 genes, including 22 tRNA genes, 2 rRNA genes, and 13 genes encoding proteins needed for ATP production. Most of the proteins in mitochondria are encoded in nuclear DNA and are translocated to mitochondria. As mitochondria are inherited by children from the mother, the hypervariable region can be used for tracking the matrilineal genetic structure of populations. Recent research revealed that cells can exchange mitochondria, and that mitochondria can exchange mitochondrial DNA between each other. Mitochondrial replacement therapy is the first causative treatment available for mitochondrial genetic disorders. On the other hand, extracellular mitochondrial DNA has been shown to induce innate immune system activation via Tolllike receptor 9. According to clinical studies and experimental research, mitochondrial DNA in the circulation might be responsible for the sepsis-like pathogenesis in patients with crush syndrome or other cause of extensive damage to tissues.