Human mitochondrial genetics

Human mitochondrial DNA
The 16,569 bp long human mitochondrial genome with the protein-coding (red, orange, yellow), ribosomal RNA (blue), and transfer RNA genes (white). Non-coding mtDNA control region in grey.
Features
Length (bp)16,569
No. of genes13 (coding genes)
24 (non coding genes)
TypeMitochondrial DNA
Complete gene lists
HGNCGene list
NCBIGene list
External map viewers
EnsemblChromosome MT
EntrezChromosome MT
NCBIChromosome MT
UCSCChromosome M
Full DNA sequences
RefSeqNC_012920 (FASTA)
GenBankJ01415 (FASTA)
Schematic karyogram showing the human genome, with 23 chromosome pairs, and the human mitochondrial genome to scale at bottom left (annotated "MT"). Its genome is relatively tiny compared to the rest, and its copy number per human cell varies from 0 (erythrocytes)[1] up to 1,500,000 (oocytes).[2]
Further information: Karyotype

Human mitochondrial genetics is the study of the genetics of human mitochondrial DNA (the DNA contained in human mitochondria). The human mitochondrial genome is the entirety of hereditary information contained in human mitochondria. Mitochondria are small structures in cells that generate energy for the cell to use, and are hence referred to as the "powerhouses" of the cell.

Mitochondrial DNA (mtDNA) is not transmitted through nuclear DNA (nDNA). In humans, as in most multicellular organisms, mitochondrial DNA is inherited only from the mother's ovum. There are theories, however, that paternal mtDNA transmission in humans can occur under certain circumstances.[3] Mitochondrial inheritance is therefore non-Mendelian, as Mendelian inheritance presumes that half the genetic material of a fertilized egg (zygote) derives from each parent.

This allowed the creation of mitochondrial DNA haplogroups to study population genetics.

Eighty percent of mitochondrial DNA codes for mitochondrial RNA, and therefore most mitochondrial DNA mutations lead to functional problems, which may be manifested as muscle disorders (myopathies).

Because they provide 30 molecules of ATP per glucose molecule in contrast to the 2 ATP molecules produced by glycolysis, mitochondria are essential to all higher organisms for sustaining life. The mitochondrial diseases are genetic disorders carried in mitochondrial DNA, or nuclear DNA coding for mitochondrial components. Slight problems with any one of the numerous enzymes used by the mitochondria can be devastating to the cell, and in turn, to the organism.

  1. ^ Cite error: The named reference pmid3178814 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference pmid28721182 was invoked but never defined (see the help page).
  3. ^ Schwartz, Marianne; Vissing, John (22 August 2002). "Paternal Inheritance of Mitochondrial DNA". New England Journal of Medicine. 347 (8): 576–580. doi:10.1056/NEJMoa020350. PMID 12192017.