Mitochondrial DNA facts for kids

Mitochondrial DNA is the small circular chromosome found inside mitochondria. These organelles found in cells have often been called the powerhouse of the cell. The mitochondria, and thus mitochondrial DNA, are passed only from mother to offspring through egg cell.

Mitochondrial DNA (mtDNA or mDNA) is the DNA in mitochondria. It is inherited only from mothers, though there are a few rare exceptions.

Mitochondria are cellular organelles in eukaryotic cells. They convert chemical energy from food into a form that cells can use, adenosine triphosphate (ATP). Mitochondrial DNA is only a small part of the DNA in a eukaryotic cell. Most of the DNA is in the cell nucleus on chromosomes. In plants, the chloroplasts have DNA as well.

In humans, mitochondrial DNA codes for 37 genes and with about 16,600 base pairs in a circle. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. The mtDNA in plants is much larger: Arabidopsis has 367 kilobytes.

Images for kids

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  Electron microscopy reveals mitochondrial DNA in discrete foci. Bars: 200 nm. (A) Cytoplasmic section after immunogold labelling with anti-DNA; gold particles marking mtDNA are found near the mitochondrial membrane (black dots in upper right). (B) Whole mount view of cytoplasm after extraction with CSK buffer and immunogold labelling with anti-DNA; mtDNA (marked by gold particles) resists extraction. From Iborra et al., 2004.

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  Animal species mtDNA base composition was retrieved from the MitoAge database and compared to their maximum life span from AnAge database.

See also

In Spanish: Genoma mitocondrial para niños