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Mitochondrial DNA and Diseases

  1. Pierre Boesch,
  2. Robert N Lightowlers,
  3. Zofia MA Chrzanowska-Lightowlers

Published Online: 15 DEC 2008

DOI: 10.1002/9780470015902.a0001462.pub2



How to Cite

Boesch, P., Lightowlers, R. N. and Chrzanowska-Lightowlers, Z. M. 2008. Mitochondrial DNA and Diseases. eLS. .

Author Information

  1. Newcastle University, Newcastle upon Tyne, UK

Publication History

  1. Published Online: 15 DEC 2008


The mitochondrial genome (mtDNA, mitochondrial deoxyribonucleic acid) is an essential source of extranuclear DNA in mammalian cells, located in the matrix of the organelle. It is much smaller than chromosomal DNA (only 16 569 bp) but thousands of copies per nucleated cell are found in nucleoprotein complexes termed nucleoids, which may constitute the heritable unit. mtDNA is maternally inherited and encodes 13 polypeptides, all fundamental for coupling cellular respiration to ATP (adenosine triphosphate) production. Consequently, mutated mtDNA can cause profound cellular dysfunction and death. Many pathogenic mtDNA mutations are known: single point mutations and rearrangements underlie clinical disorders known as mitochondrial cytopathies or encephalomyopathies; several nuclear gene mutations are known to cause mtDNA rearrangements; there exists an association between mtDNA deletions and the ageing process. Models explain how deletions may occur, but it is unknown how these deleted molecules predominate in individual cells over time, a process termed clonal expansion.


  • mitochondrial DNA;
  • mitochondrial disease;
  • heteroplasmy;
  • homoplasmy