Which animal/plant/anything has smallest length genome?
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Since you said plant/animal/anything, I offer the smallest genomes in various categories...
(Kb means Kilobases, Mb means Megabases. 1 Kb = 1000 base pairs, 1Mb = 1000Kb)
- Smallest plant genome: Genlisea margaretae at 63Mb (Greilhuber et al., 2006)
- Smallest animal genome: Pratylenchus coffeae (nematode worm) at 20Mb (Animal Genome Size DB)
- Smallest vertebrate genome: Tetraodon nigroviridis (pufferfish) at 385Mb (Jailon et al., 2004)
- Smallest eukaryote: Encephalitozoon cuniculi (microsporidian) at 2.9Mb (Vivarès & Méténier, 2004)
- Smallest free-living bacterial genome: Nanoarchaeum eqitans at 491Kb (Waters et al., 2003)
- Smallest bacterial genome: Carsonella ruddii (endosymbiont) at 160Kb (Nakabachi et al., 2006)
- Smallest genome of anything: Circovirus at 1.8Kb (only 2 proteins!!) (Chen et al., 2003)
Refs...
- Chen, C.-L., Chang, P.-C., Lee, M.-S., Shien, J.-H., Ou, S.-J. & Shieh, H.K. (2003) Nucleotide sequences of goose circovirus isolated in Taiwan. Avian Pathology: Journal of the W.V.P.A. 32 (2), 165–171.
- Greilhuber, J., Borsch, T., Müller, K., Worberg, A., Porembski, S. & Barthlott, W. (2006) Smallest Angiosperm Genomes Found in Lentibulariaceae, with Chromosomes of Bacterial Size. Plant Biology. 8 (6), 770–777.
- Jaillon, O., Aury, J.-M., Brunet, F., Petit, J.-L., Stange-Thomann, N., Mauceli, E., Bouneau, L., Fischer, C., Ozouf-Costaz, C., Bernot, A., Nicaud, S., Jaffe, D., Fisher, S., Lutfalla, G., et al. (2004) Genome duplication in the teleost fish Tetraodon nigroviridis reveals the early vertebrate proto-karyotype. Nature. 431 (7011), 946–957.
- Nakabachi, A., Yamashita, A., Toh, H., Ishikawa, H., Dunbar, H.E., Moran, N.A. & Hattori, M. (2006) The 160-Kilobase Genome of the Bacterial Endosymbiont Carsonella. Science. 314 (5797), 267–267.
- Vivarès, C.P. & Méténier, G. (2004) Opportunistic Infections: Toxoplasma, Sarcocystis, and Microsporidia. In: World Class Parasites. Springer US. pp. 215–242.
- Waters, E., Hohn, M.J., Ahel, I., Graham, D.E., Adams, M.D., Barnstead, M., Beeson, K.Y., Bibbs, L., Bolanos, R., Keller, M., Kretz, K., Lin, X., Mathur, E., Ni, J., et al. (2003) The genome of Nanoarchaeum equitans: insights into early archaeal evolution and derived parasitism. Proceedings of the National Academy of Sciences of the United States of America. 100 (22), 12984–12988.
Glorfindel
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Rik Smith-Unna
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1Well done! How did you find these? – Mar 12 '12 at 16:36
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8The plant and bacterial ones I had floating around in my memory having read about them previously, so a bit of googling confirmed the names. The animal ones I got from the Animal Genome Size DB, and from Wikipedia. I guessed that viral genomes would be the smallest, so I also searched for the smallest viral genome. Then I went back to the literature (by searching Google Scholar for organism name + "genome size") to check all my facts and provide reliable references. – Rik Smith-Unna Mar 12 '12 at 18:43
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2Nice answer Richard. – Poshpaws Mar 13 '12 at 11:38
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"Smallest genome of anything" is wrong. There are virus-like elements like viroids with as little as ~200 bp 'genomes'. Some viroids have as little as one RNA enzyme, others have not even this. – arara Feb 16 '23 at 13:22
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Smallest free-living bacterial genome: Nanoarchaeum eqitans at 491Kb (Waters et al., 2003) I downloaded this paper it says that this is archaea and its obligate symbiont not a free living bacteria. Please read carefully and then upload it. – manish Aug 14 '15 at 10:10
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I want to say Mycoplasma genitalium with a genome size of 582,970 bp. Turns out the answer is Nanoarchaeum eqitans with a genome of 490,885 bp.
bobthejoe
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5That's the smallest genome of a free-living organism. And until 2003 you would have been right about Mycoplasma, which were previously the smallest known in that category. – Rik Smith-Unna Mar 12 '12 at 00:38
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Both Mycoplasma genitalium and Nanoarchaeum equitans are obligate parasites / endosymbionts. This means that they depend heavily on their host to support their vital functions and they have lost many of their own genes.
A really free-living organism with an extremely small genome (~1309 kbp, 1354 genes) is the heterotrophic marine alpha-proteobacterium Pelagibacter ubique [1].
See a larger analysis here: https://alamot.github.io/smallest_genome/
[1]: https://www.ncbi.nlm.nih.gov/pubmed/16109880 Giovannoni SJ, Tripp HJ, Givan S, Podar M, Vergin KL, et al. (2005). «Genome streamlining in a cosmopolitan oceanic bacterium». Science 309: 1242–1245.
Alamot
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