On the other hand, every known living creature on Earth uses essentially the same DNA-based genetic code, which suggests abiogenesis occurred only once in the planet’s history.
well this alone doesn’t suggest abiogenesis occurred only once: just that if any other abiogenesis occurred it was outcompeted by DNA replicators.
when i was in school there was a theory that RNA was a remnant of pre-DNA abiogenesis: either that it bootstrapped DNA life, or that it was one such distinct line which “lost” to DNA. in the latter case, hard to say how many other lines there were which left no evidence visible today, or even how many lines/abiogenesis events would have occurred if not for DNA replicators altering the environment and available resources. hopefully research has provided better predictions here that i just haven’t heard about yet.
well this alone doesn’t suggest abiogenesis occurred only once: just that if any other abiogenesis occurred it was outcompeted by DNA replicators.
when i was in school there was a theory that RNA was a remnant of pre-DNA abiogenesis: either that it bootstrapped DNA life, or that it was one such distinct line which “lost” to DNA. in the latter case, hard to say how many other lines there were which left no evidence visible today, or even how many lines/abiogenesis events would have occurred if not for DNA replicators altering the environment and available resources. hopefully research has provided better predictions here that i just haven’t heard about yet.