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pfdietzyesterday at 12:07 PM2 repliesview on HN

It contains nucleobases. But does it contain ribose, or ribose linked to the nucleobases, or to phosphates? And more generally, does it also contain a grab bag of related chemicals that are not building blocks? The existence of such blocks as minor constituents of a soup of random chemicals doesn't mean much, especially as the concentration of any such constituent declines exponentially with its complexity.


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ceejayozyesterday at 12:25 PM

https://www.nasa.gov/missions/osiris-rex/sugars-gum-stardust...

> The five-carbon sugar ribose and, for the first time in an extraterrestrial sample, six-carbon glucose were found.

The soup does matter, as does finding that the ingredients are everywhere.

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HarHarVeryFunnyyesterday at 12:46 PM

It's a sample of one, but I think the takeaway is just that if the nucleobases are present on a random asteroid then they probably commonly occur. Of course as you note it takes a lot more than that to form these into nucleic acids.

I would guess there is a more primitive stage in the emergence of life where self-replicating soups (Kaufmann: metabolisms), including things like nucleobases and amino acids, capable of collective replication/expansion exist, before we get anything as sophisticated as nucleic acids and structural encoding.

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