The experiment can still be relevant to evolution of greater complexity in the RNA world even if the evolving system does not consist purely of RNA. It’s a common misunderstanding to think the term ‘RNA world’ refers exclusively to a time in life’s evolution where there was only RNA and nothing else.
But the term is actually used more broadly in the field to refer both to hypothetical stages consisting only of RNA, but also extends to include systems consisting of RNA+small uncoded peptides, and RNA+translation systems (an RNA+protein world). Admittedly researchers in the field are not always perfectly clear on these nuances.
Certainly, this system is not conceived to be informative about the transition from a pure RNA world into an RNA+protein world, but simply about how competition among RNA-based replicating systems can favor cooperation and thus evolve greater complexity.
Well the translation system does not perform replication. It translates mRNA into protein. Of course in this system the translation system is required to decode the RNA to produce the RNA replicase enzyme that replicates the RNA and no evolution would take place in this experiment without that translation system.
I think there’s a space for some nuance in understanding of the terms being used, and there are ways in which an experiment can be informative about a process without it perfectly representing that process in every imaginable aspect.
I don’t think that’s a substantive response. I am deadly serious, and everything I wrote there is absolutely true.
No, the experiment was relevant to the elucidation of plausible pathways for the emergence of a feature (not the entire aspects of the RNA world) that is present in any world with populations capable of replication and that feature is complexity. Replication is just one ingredient for the evolution of complexity and the mechanism via which the replication should happen is irrelevant to the research problem addressed by the investigators: they simply needed replication to happen. They mixed that (replication) in with other ingredients required for Darwinian evolution and complexity arose.
How the study is “overblown hype” eludes me, because it addresses (and quite nicely) a serious problem about the origin of life which is the emergence of complexity.
Um, maybe this is because the paper in question is not about “the necessary replication”, but rather about how ensembles of functional, interactive, cooperating RNAs might evolve from simple precursors.
No matter how much one might assert otherwise, this is an important issue that is central to our understanding of the origin of life.
I left one teaser above about alternative replication scenarios that others are studying. Another teaser is the title of a very old paper that addresses your objection, @theaz101 - " Synthesis of Oligonucleotides
by Proteinoid Microspheres Acting on ATP" (Jungck, J.R., Fox, S.W., Naturwissenschaften 60, 425–427 (t973). Enjoy!
“the first RNA, that most would agree would be the primordial replicating genetic species”
That is grossly unfair to the origins of life community, of which there was a member for many years. On the contrary, it is recognised that RNA is an extremely unlikely molecule to have formed unless there was some older system for accumulating inherited information.
I am not sure I follow. In the context of the roadmap I was using to discuss the criticisms of the paper of interest, this is a fairly safe statement. Maybe the term “primordial genetic species” needs some qualifiers?
To put it at its simplest, ribose doesn’t just happen. A system capable of producing and using ribose must already have a sophisticated metabolism. Hence interest in other less impausible precursors such as peptide nucleic acid, Peptide nucleic acid - Wikipedia.
But perhaps I’ve projected my own skepticism about the RNA world onto colleagues who don’t share it. Let me retreat to saying that many in the OoL community regard the RNA world hypothesis as describing a plausible stage in the emergence of life on earth, but like me think that even if so, its complexity implies the existence of earlier systems capable of replication and Darwinian evolution
I don’t particularly care how it happened, but I can tell you that the origins of life claims here are not meaningful.
These molecules did not exist on early earth until after life began – no pure right-handed ribose, no free phosphate groups, nothing to build these into activated nucleotides, no E. coli translation systems. You can fantasize them into existence all you want, but the science says no. Then when they put this collection of life molecules into a purified, controlled lab setting with a very careful recipe it is hardly surprising that they behave like life molecules. Oh wait! They ARE life molecules! The most remarkable thing here is how “what life molecules do” is spun into massively overhyped claims that this relates to origins of life somehow.
Science works by building and rigorously testing hypothesis. The hypotheses (in bold) tested by the investigators in that study are found in the “Introduction” section of their paper: “An origins-of-life scenario depicts Darwinian evolution from self-replicating molecules, such as RNA, toward complex living systems. How molecular replicators could develop complexity by continuously expanding information and functions is a central issue in prebiotic evolution. An expected route for complexification is that novel RNA replicators successively emerged and co-replicated so that increased genetic information can be stored at a population level, before their assembly into a long genome”"
They conducted good science, so your points here aren’t “meaningful” to me.
All of these things are irrelevant to the questions addressed in that study. There was an RNA world (and possibly other worlds with self-replicating molecules before that) and complexity arose in populations of RNA molecules existing at that time. The study is focused on how complexity arose after the RNA world emerged, thus making the problem of how the RNA world emerged irrelevant.
Read the paper again bro, the science says yes, with absolutely no fantasies involved.
This implies “life molecules” behave differently from other molecules. Can you distinguish between “life molecules” and other molecules in terms of behaviour?
Again, provide the distinction between “life molecules” and other molecules in the context of behaviour?
If you looking for overhype, Peaceful Science is the least go-to place for that. There are well-trained hype killers here. No one “here” has hyped anything from that study, but the study produced very interesting results which merit more discussion.
More importantly, the researchers performed good science - testing hypotheses as rigorously as possible.
Why not do an experiment to show that petroleum burns, then conclude that was partly responsible for keeping the early earth warmer when the sun was less bright? Ignore the fact that an early earth source for petroleum and oxygen is missing, so the relevance of the argument is unknown. People could argue that in one narrow sense it’s “good science” but it would almost certainly be irrelevant.
That is what’s happening in this study where there are a lot more missing parts. Ignore the lack of early earth sources for naturally occuring (not life-generated) pure right-handed ribose, phosphates, activated nucleotides, and E. coli translation systems, or an environment of pure water droplets gently agitated in purified oil. And then suggest this as an example of what might have happened on early earth. Just seems to me there’s a non-sequitur here.
@Michael_Okoko “life molecules” are molecules manufactured by living cells, but otherwise they are not naturally occuring. As you quoted me:
First, this is not the answer to the question I asked. Let me reiterate, what is the distinction in behaviour between “life molecules” and other molecules, since your earlier arguments suggested life molecules act differently from other molecules?
Second, bicarbonate is a molecule produced by living organisms, but it also produced by geochemical processes and that contradicts your definition of a life molecule. Carbon dioxide also contradicts your definition because we make it, so do volcanoes.
Third, are you saying carbon dioxide did not exist on the early earth prior to the evolution of life as we know it?