The idea of a full continuity between chemistry and biology is so tantalizing and beautifully simple. Great synopsis on that article!

"a study by chemists Addy Pross and Robert Pascal"

I thought for a moment I had missed something. But no, it is the same sweeping ideas that are so often promoted in this area.

I can understand that they are alluring. But they are based on some fundamental misunderstandings of biology. From my viewpoint of studying astrobiology, here they are:

- The idea that we need new mechanisms for chemical evolution.

First, we observe that chemical evolution works throughout time and space in the universe.

Second, the speed with which life was established on Earth speaks for an easy and/or often enough attempted process transitioning to biological evolution.

- The idea that evolution isn't falsifiable.

Evolution gives phylogenies, which by construction are enormously constrained combinatorial networks, a handful of potential pathways (species lineages) in a truly vast space of networks. We don't need,nor ask for, the exact pathways as local resolution can be too low, yet the precision of the entire network staggering. (Many orders of magnitude certainty.)

They are tested by adding species. Famously "a precambrian rabbit" falsifies the standard phylogeny. Here it would be "pre-Earth genes", say. Eminently testable, all gene or protein fold phylogenies converge on ~ 4 billion years as the earliest "rabbit".

- The idea that biology is an equilibrium and/or stability regime.

The thermodynamics of the planet (biosphere driven by the Sun, radiating to space) rejects that. The evolutionary biological process is as such very little coupled to thermodynamics and there is no inherent ecological (population) stability.

Instead, where is astrobiology today?

- Lane & Martin has shown that classical bottleneck constraints (chicken-or-egg problems) makes alkaline hydrothermal vent chemistry preceding earliest autotroph metabolism. As expected, these mechanisms were as they note in the paper homologous chemical networks.

- Thermodynamics shows that a) RNA is the only pre-protein nucleotide that fulfill the thermodynamic bound for replicators, b) a random strand 'gas' population of RNA _will_ crystallize to a replicator within ~ 30 000 years in the phosphate activating environment of alkaline hydrothermal vents.

The pathways from replicator strands to genomes are legion, but the simplest goes through a simplest possible brwonian ratchet making RNA strand replication one way and unchained from vent thermal environment. Coincidentally, the minimum ratchet is a 3 basepair codon polypeptide, the initially random sequencing (no function except ratcheting) consistent with early fold properties (random peptides outside of fold function).

These two bottleneck systems marry well, the first genomes would support local organics producing metabolic cellular compartments and vice versa.

I agree with im_an_optimist,

Great synopsis on that article!

Really nice article. I can't say that I already thought that this was a popular perspective, but from the biochemistry that I have taken, I always assumed that 'dynamic equilibrium' was a cornerstone of biological sciences, and such, I would have guessed that it would have more deeply pervaded theories of biogenesis. I come from a physics background, and for me, life has always been a question of thermodynamics. Life is a process, not a state, and as such, the replicative nature of biological processes are what increase the exergy they can draw upon, putting them into a supra-chemical realm. Or perhaps more simply, these are chemical reactions that can draw upon another well of energy which is not available to abiotic reactions. I suppose that is Darwinian chemistry.

I recall b_b mentioning some physicists that posited that life is an avenue of thermodynamic equilibrium that can't be avoided under certain conditions. To me, that seems a reasonable way of looking at things. It would also suggest that life must be fairly common, or at least proportional to the number of conditions that exist that would allow for it.

I guess what I am saying, is that I think physicists and biologists need to have lunch together more often. :) At any rate, I completely agree that this perspective can be applied to other areas. IMO there are strong parallels between the abiotic-to-biotic 'transition', and the 'animate-to-conscious' transition.