[gus_massa]

The definition of minimal life as a thing with a single nucleotide is weird. If I have to pick an arbitrary number, I'd choose at least 100. (Anyway, with their model they get that when the Earth appeared, "life" had ~10000 nucleotides.)

> In particular, photosynthesis or chemosynthesis is needed to be independent from organic resources.

It's weird because the current estimation is that photosynthesis appeared like 1000 millions years after the fist cell. So if this article were correct and the initial cells population came from space, they probably would no have photosynthesis.

[JMTQp8lwXL]

Whatever existed prior to life probably had life-like qualities, but couldn't fully meet the criteria, e.g., viruses. So even 0 nucleotides could make sense, if this prototypical organism had other features, and at some point, nucleotides arrived later.

[gus_massa]

When the chains are very small, you can start to hope you are lucky and get the correct one. The ocean has 1.3 * 10^18 m^3 (3.5 * 10^20 gallons). If we assume 1 random DNA chain per cubic meter, that is like 4^30, so it's enough to have all the chains with 30 bases.

(With 1 molecule per cm^3, you get like 10 more bases in locations for random chains.)

It's actually more complicated, because shallow part of the sea or fumes near ocean rigs may have more concentration, and 1 molecule per cubic meter is a very low concentration. Anyway, extrapolating to 1 base is too extreme.

Also, they had a nice fit for DNA based life, and they discuss the RNA World hypothesis, but it's not clear that the fit for DNA can be extrapolated to the RNA or whatever was used before.

(There is a recent paper that propose a mix of RNA and DNA instead of a pure RNA word. We still don't know.)