Mitochondrial DNA: structure, inheritance, and applications

Mitochondrial DNA definition and cellular role

Mitochondrial DNA (mtDNA) is the small circular chromosome located inside mitochondria, the organelles that convert chemical energy from organic compounds into ATP. It represents only a minor fraction of a eukaryotic cell’s total DNA, since most genetic material is in the nucleus (and in plants/algae, additional DNA is found in plastids such as chloroplasts). In humans, mtDNA encodes 13 essential protein subunits of the oxidative phosphorylation (OXPHOS) system, along with 2 rRNAs and 22 tRNAs, which together support cellular energy conversion. mtDNA is thought to originate from bacterial genomes through endosymbiosis, and its structure and size vary widely across organisms (e.g., circular in most animals, but linear or heterogeneous forms in some protists and other lineages). Replication and transcription are controlled by strand-specific mechanisms and regulatory noncoding regions (such as the human D-loop), and mtDNA is maintained by repair pathways distinct from nuclear DNA repair. Functionally, mtDNA is also central to inheritance patterns (typically maternal), evolutionary studies (due to its relatively fast evolution in animals), and applications such as forensic identification when nuclear DNA is degraded.

0/2 modes complete

Endosymbiotic origin of mitochondrial genomes

0/2 modes complete