Actually the authors of this paper say that the system underwent evolution. First sentence 4th paragraph.
"The catalytic properties of the cross-replicating RNA enzymes were improved by the use of in vitro evolution, optimizing the two component reactions in parallel and seeking solutions that would apply to both reactions when conducted in the cross-catalytic format "
The follow up studies, the ones that cite this paper, use the word evolution much more liberally.
That is a very cool paper. They're funded by NASA!
these prebiotic polymers DID have modifiable heritable traits. It's believed that the first autocatalytic repicating biomolecules were similar to RNA. They would have been mutating faster than RNA does today because they had no nucleotide repair pathways.
Hey there
I understand that how life first came to be is still being worked out. I see the topic of abiogenesis as comparable to the creation, really. That is the start of life that cannot be explained with confidence.
What I do not understand is the principle of minimum viable population size as it applies to the first living cells.
This link talks about a minimum viable population size of 4169 individuals.
ScienceDirect - Biological Conservation : Minimum viable population size: A meta-analysis of 30 years of published estimates
So when the first cells originated were they stuck to a rock or floating around in the sea or some pond.
We see that with research into Horizontal Gene transfer, now found in prokaryotes, that LUCA is no more a certainty. It appears that the new models speak to multiple arisings of primitive cells that transfered genes.
This leads me to a conclusion that all life that arose by some natural means was very similar. So similar in genetic makeup were these cells that they were able to negotiate gene transfer.
How does this minimum viable population fit in here? How did primtive cells stuck to a rock manage to transfer genes? How did cells floating around in the ocean or in a pond manage to do so?
Were there hundreds of thousands of these primitive cells all having come into existence with the same genetic structure or just a few that managed to find each other or is common thinking suggesting still just one cell, coming to life one time?
What is also interesting is that if earth or the universe are strewen with the precursors for life one would expect life would have arisen on more than one occasion with a very different genetic makeup. This does not appear to be the case.
I understand the initial RNA world, but RNA still has alleles don't they? I expect that RNA in all life must also be the same. However this does not appear to be the case. There are many deletions. If primitive cells had RNA, did RNA arise after reproduction was enabled or before. It appears reproduction cannot exist without a genetic mechanism already assembled to support it.
Structurally different alleles of the ath-MIR824 microRNA precursor are maintained at high frequency in Arabidopsis thaliana
"The modes of HGT are transformation. This actually appears to require other genetic material around at the time to uptake. Transduction requires a virus to be around for HGT to occur this way, Bacterial conjucation requires contact of the cells, Gene transfer agents also appear to need virus around. How did the fist living cells ever manage to negotiate gene transfer, particularly in the oceans re thermal vent abiogenesis? There was just bacteria, no virus yet evolved and no other genetic material was around at the time. The planet was lifeless apart from these primitive cells.
Nor is abiogenesis (the origin of the first life) due purely to chance. Atoms and molecules arrange themselves not purely randomly, but according to their chemical properties. In the case of carbon atoms especially, this means complex molecules are sure to form spontaneously, and these complex molecules can influence each other to create even more complex molecules. Once a molecule forms that is approximately self-replicating, natural selection will guide the formation of ever more efficient replicators. The first self-replicating object didn't need to be as complex as a modern cell or even a strand of DNA. Some self-replicating molecules are not really all that complex (as organic molecules go). " from the 5 misconceptions re evolution thread.
This info appears to be saying that all life that arises is going to be the same as it is not random but will arise according to their chemical properties. This article also suggests that scientists are uncertain how many cells were initially formed, yet they were numerous enough to negotiate HGT.
If only a few hundred cells arose initially, how come they did not die out according to this minimum viable population theory? Does it apply to asexually reproductive organisms?