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That's what I was trying to say; I'm in no way a panspermia fan. I was responding primarily to the line "perhaps DNA(+RNA) is the only molecule with the right
by gomijacogeo 7y ago
That's what I was trying to say; I'm in no way a panspermia fan. I was responding primarily to the line "perhaps DNA(+RNA) is the only molecule with the right properties to act as genetic material" with the notion that it was probably more special because it was first rather than something intrinsic about the DNA->RNA->ribosome system that made it inevitable. If we could roll the clock back 4.mumble billion years, we'd probably still get life that had a separation between code and structure, but what that code was and what that structure looked like might have been pretty different.
- JoeAltmaier 7y agoI'm not sure there is anything else with the flexibility of D/RNA. Its self-replicating property is fundamental. Is there something else known to work anything like this?
- gomijacogeo 7y agoSome possible alternatives are covered here: https://en.wikipedia.org/wiki/Nucleic_acid_analogue https://en.wikipedia.org/wiki/Nucleic_acid_analogue And I agree that RNA and DNA are pretty good molecules and probably close to some notion of 'optimal'. The ribosome, however, is big and complicated and there are probably millions of different ways something like that could have come about and that would affect the 3-base codon, protein structures, etc. Also, look at the contortions DNA has to go through to copy what's called the "lagging strand". Clearly duplicating double-stranded DNA did not come early or easily; it's pretty obvious a system bolted on top of some other, older system. https://en.wikipedia.org/wiki/DNA_replication#Lagging_strand https://en.wikipedia.org/wiki/DNA_replication#Lagging_strand