Editing Mitochondrial DNA (section)

=== Animals ===
Most ([[bilateria]]n) animals have a circular mitochondrial genome. [[Medusozoa]] and [[Calcareous sponge|calcarea]] [[clade]]s however include species with linear mitochondrial chromosomes.<ref>{{Cite journal |vauthors=Lavrov DV, Pett W |date=September 2016 |title=Animal Mitochondrial DNA as We Do Not Know It: mt-Genome Organization and Evolution in Nonbilaterian Lineages |journal=Genome Biology and Evolution |volume=8 |issue=9 |pages=2896–2913 |doi=10.1093/gbe/evw195 |pmc=5633667 |pmid=27557826}}</ref> With a few exceptions, animals have 37 genes in their mitochondrial DNA: 13 for [[protein]]s, 22 for [[transfer RNA|tRNAs]], and 2 for [[ribosomal RNA|rRNAs]].<ref name="Boore1999">{{Cite journal |last=Boore |first=J. L. |date=1 April 1999 |title=Animal mitochondrial genomes |journal=Nucleic Acids Research |volume=27 |issue=8 |pages=1767–1780 |doi=10.1093/nar/27.8.1767 |pmc=148383 |pmid=10101183}}</ref>

Mitochondrial genomes for animals average about 16,000 base pairs in length.<ref name="Boore1999" /> The anemone ''Isarachnanthus nocturnus'' has the largest mitochondrial genome of any animal at 80,923 bp.<ref>{{Cite journal |vauthors=Stampar SN, Broe MB, Macrander J, Reitzel AM, Brugler MR, Daly M |date=April 2019 |title=Linear Mitochondrial Genome in Anthozoa (Cnidaria): A Case Study in Ceriantharia |journal=Scientific Reports |volume=9 |issue=1 |page=6094 |bibcode=2019NatSR...9.6094S |doi=10.1038/s41598-019-42621-z |pmc=6465557 |pmid=30988357}}</ref> The smallest known mitochondrial genome in animals belongs to the comb jelly ''[[Vallicula multiformis]]'', which consist of 9,961 bp.<ref>[https://www.biorxiv.org/content/10.1101/366880v1.full Polymorphism within the mitochondrial genome of the ctenophore, Pleurobrachia bachei and its ongoing rapid evolution - bioRxiv]</ref>

In February 2020, a jellyfish-related parasite – ''[[Henneguya salminicola]]'' – was discovered that lacks a mitochondrial genome but retains structures deemed mitochondrion-related organelles. Moreover, nuclear DNA genes involved in aerobic respiration and mitochondrial DNA replication and transcription were either absent or present only as [[pseudogene]]s. This is the first multicellular organism known to have this absence of aerobic respiration and live completely free of oxygen dependency.<ref>{{Cite journal |display-authors=6 |vauthors=Yahalomi D, Atkinson SD, Neuhof M, Chang ES, Philippe H, Cartwright P, Bartholomew JL, Huchon D |date=March 2020 |title=A cnidarian parasite of salmon (Myxozoa: ''Henneguya'') lacks a mitochondrial genome |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=117 |issue=10 |pages=5358–5363 |bibcode=2020PNAS..117.5358Y |doi=10.1073/pnas.1909907117 |pmc=7071853 |pmid=32094163 |doi-access=free}}</ref><ref>{{Cite web |date=25 February 2020 |title=Scientists Find The First-Ever Animal That Doesn't Need Oxygen to Survive |url=https://www.sciencealert.com/this-is-the-first-known-animal-that-doesn-t-need-oxygen-to-survive |url-status=live |archive-url=https://web.archive.org/web/20200225075450/https://www.sciencealert.com/this-is-the-first-known-animal-that-doesn-t-need-oxygen-to-survive |archive-date=25 February 2020 |access-date=2020-02-25 |website=ScienceAlert |language=en-gb |vauthors=Starr M}}</ref>