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Which animal/plant/anything has smallest length genome?

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3 Answers 3

up vote 41 down vote accepted

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)


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Well done! How did you find these? – user560 Mar 12 '12 at 16:36
The 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. – Richard Smith-Unna Mar 12 '12 at 18:43
Nice answer Richard. – Poshpaws Mar 13 '12 at 11:38

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.

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That'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. – Richard Smith-Unna Mar 12 '12 at 0:38

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.

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Can you please edit your answer and add a link for the reference? – Chris Aug 14 at 10:16

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