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Mitochondrial Genome

  1. Cecilia Saccone

Published Online: 15 FEB 2011

DOI: 10.1002/9780470015902.a0005069.pub2

eLS

eLS

How to Cite

Saccone, C. 2011. Mitochondrial Genome. eLS. .

Author Information

  1. University of Bari, Bari, Italy

Publication History

  1. Published Online: 15 FEB 2011

Abstract

Mitochondria are cytoplasmic organelles present in all eukaryotic cells that are able to respire. They possess their own genetic system whose size and organisation are quite variable in plants, protists and fungi. A certain degree of structural variability is observed also in Metazoa, whereas mitochondrial deoxyribonucleic acid (mtDNA) is rather small but constant in vertebrate cells (about 17kb). The genetic content and organisation of human mtDNA is very similar in all vertebrates. It consists of two ribosomal ribonucleic acid (RNA) genes, 13 protein-coding genes and 22 transfer RNAs. All other mitochondrial products are coded by nuclear DNA and transported into the mitochondrion. Mitochondrial genetic system has a uni-directional way of inheritance, and it is present in cell in a multicopy state. mtDNA replication, transcription and translation are also very peculiar. Evolutionary origin of mitochondria has been described through the endosymbiotic theory.

Key Concepts:

  • Mitochondria are eukaryotic cell organelles with their own genome.

  • Mitochondrial genome shows great structural variability in most eukaryotic taxa but are quite stable for content and organisation in Metazoans.

  • mtDNA has a poor gene content; mitochondrial protein genes encode for respiratory chain subunits, fundamental for cell energy production.

  • The mitochondrial genome has bacterial origin, with several peculiar features about its replication and expression.

  • mtDNA is a multicopy genome that is uni-parentally transmitted and does not undergo recombination.

  • Evolution of mtDNA (within Metazoa) is lineage-specific.

Keywords:

  • organelle DNA;
  • oxidative phosphorylation;
  • energy production;
  • D loop;
  • endosymbiosis;
  • uni-directional inheritance;
  • recombination;
  • selection;
  • mutation;
  • phylogenetic inference