[pretzellogician]

Very impressive! To be clear, this is not the smallest known bacterial genome; only the smallest known archaeal bacterial genome, at 238k base pairs.

In the article they mention C. ruddii, with a smaller 159k base pair genome.

But according to wikipedia, it seems N. deltocephalinicola, at 112k base pairs, may be the smallest known bacterial genome. https://en.wikipedia.org/wiki/Nasuia_deltocephalinicola

[oersted]

That’s interesting. The main difference seems to be that those other tiny organisms only encode how to produce some metabolic products for the host but cannot reproduce independently, so they are quite close to being organelles. Instead, this new one pretty much only produces the proteins it needs to reproduce and nothing for the host.

The new one with 238 kbp:

> Sukunaarchaeum encodes the barest minimum of proteins for its own replication, and that’s about all. Most strangely, its genome is missing any hints of the genes required to process and build molecules, outside of those needed to reproduce.

Referencing the 159 kbp one:

> However, these and other super-small bacteria have metabolic genes to produce nutrients, such as amino acids and vitamins, for their hosts. Instead, their genome has cast off much of their ability to reproduce on their own.

[flobosg]

A nitpick: Although similar in some aspects, archaea are not bacteria; they are classified under their own phylogenetic domain.