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The Koonin threshold for the Origin of Life on Earth

A 'review' of The Logic of Chance
by Gert Korthof   3 Jan 2013



The Logic of Chance
Eugene Koonin (2011,2012)
The Logic of Chance. The Nature and Origin of Biological Evolution.
Pearson, FT Press hardback 516 pp. (1)
In this review I focus on a spectacular claim in chapter 12 and Appendix B that sets it apart from the rest of the book and from the opinion of almost every evolutionary biologist. For this review I ignore the rest of the book. So this is not a review of the book (impossible anyway).

In Chapter 12 Koonin discusses the origin of life, that is: the emergence of translation, replication, metabolism and membranes. Life as it is today is a DNA-protein world. However, the DNA-protein world is a non-starter. The DNA-protein world faces the proverbial chicken-and-egg problem: what comes first, DNA or protein? DNA is needed to produced proteins and DNA needs proteins to get replicated, transcribed and translated into proteins. To solve this chicken-and-egg problem, the RNA-world is logical inevitable. RNA can function both as protein (enzyme) and replicator. However, even under the best-case scenario, the RNA-World hardly has the potential to evolve beyond very simple "organisms" (p. 366). The path from a putative RNA World to a translation system (DNA-protein world) is incredibly steep (p. 376). The hardest problem is that evolution by natural selection can only start after replication with sufficient fidelity is established (2). Not withstanding all scientific progress, we currently do not have a credible solution to these problems (4).


Why is it so difficult to evolve a DNA-protein world from a RNA-world? Here is Koonin's specification of the requirements of a coupled replication-translation system (p. 435) (these calculations are the same as in: 3 ):

2 rRNAs with a total of at least:1,000 nucleotides
10 primitive adaptors of about 30 nucleotides each: 300 nucleotides
at least 1 RNA encoding a replicase: 500 nucleotides
 
Total (at least 13 RNA molecules):1,800 nucleotides

The probability of the spontaneous origin of this is: P < 10-1018. The spontaneous origin of 1,800 nucleotides is the Koonin-threshold for the origin of life and evolution. No Origin of Life (OOL) researcher put it more clearly and dramatically than Koonin. Please note 1,800 nucleotides is a minimum. Every OOL researcher that skips over the Koonin threshold makes a serious scientific oversight. Here are two graphical representations of the Koonin threshold.

KOONIN FIGURE 12-6
Figure 12-6 The prebiological and biological stages of the origin of life:
the transition from anthropic causality to biological evolution.

Figure 12-6 shows that at most ribozymes could spontaneously originate, but not a coupled replication-translation system (the DNA-protein world). So, if ribozymes are the beginnings of the RNA-world, Koonin claims that the RNA-world would come to a halt before a replication-translation system emerged. In our universe, certainly on our earth (5), the RNA-world would be a dead end.

KOONIN FIGURE 12-7
Figure 12-7 Pruning of evolutionary trajectories at the threshold of biological evolution.
A: chemical evolution. B: emergence of biological evolution.
(Anthropic selection means: only the universe in which the transition happened evolved observers).
(Both figures are from the pdf edition. Hardback does not contain color illustrations)

In figure 12-7B the threshold of biological evolution would equal 1,800 nucleotides. Despite this, life exists on this earth. Now, Koonin invokes a radical alternative: Eternal Inflation Cosmology. The Many Worlds in One (MWO) changes the very definition of what is possible, likely, and random in such a way that the probability of the realization of any scenario in an infinite multiverse is exactly 1.
"Thus, spontaneous emergence of complex systems that would have to be considered virtually impossible in a finite universe becomes not only possible, but inevitable under MWO." (p. 385).
"Specifically, it becomes conceivable that the breakthrough stage for the onset of biological evolution could have been a primitive coupled replication-translation system that emerged by chance" (p.392 my emphasis).
This is the most unorthodox, subversive claim in the whole 516 page book. This radical change in thinking must have happened 2007 May 31 when Koonin published an 'optimistic' mainstream publication with Yuri Wolf (2) and a 'pessimistic' publication (3) without coauthor. The second publication has been reviewed by four researchers. One reviewer (Eric Bapteste) was afraid that Koonin's views "could open a huge door to the tenants of intelligent design". Koonin replied that "Properly interpreted, the anthropic principle is a death knell to ID" and that biologists should not stop publishing research on hard problems in evolutionary biology and should not declare these hard problems solved. The ID crowd will interpret these results as support for their cause anyway." I fully agree with Koonin. David Krakauer warns for the danger of invoking the infinite multi-verse: "as well assert that all observed biological order emerged in one step, including the complete evolutionary history of life." According to the fourth reviewer (Itai Yanai) the present model represents the first one to account for the origin of life by explicitly invoking the anthropic principle. The anthropic principle means that only universes in which the transition to Darwinian evolution happened evolved observers. The other universes do not contain (complex) life and thus no observers.

What should we think of this extraordinary scenario? Koonin claims it is falsifiable. According to Koonin his hypothesis can be falsified by the demonstration that the RNA-world can produce a translation system. But if he holds that is a serious possibility, his extravagant proposal cannot be taken very seriously. He could as well have said "We don't know" and hope for a future solution. It is true that nobody before gave such a detailed calculation of a threshold for biological evolution. However, he should have given more details and background information of the calculation of 1,800 nucleotides threshold and not relegated it to the Appendix. It should have been included in chapter 12. For, extraordinary claims should be build on very well researched evidence.
Finally, why not do an experiment? If only 13 RNA molecules with a total length of 1,800 nucleotides are necessary, it should not be that difficult to synthesize them and bring in the right chemical environment and observe the origin of life. If sequences are not (precisely) known, why not start with random sequences? That could verify or falsify Koonin's theory.

       Notes  

  1. There is a pdf of the book available on the internet with full color illustrations! The hardback does not contain color illustrations and many are of low quality (f.e. figure 5-2 is completely black). So the hardback isn't worth the money.
  2. Yuri I Wolf and Eugene V Koonin (2007) On the origin of the translation system and the genetic code in the RNA world by means of natural selection, exaptation, and subfunctionalization, Biol Direct. 2007; 2: 14. Free access. Here the authors show that what I call 'the Koonin threshold' is based on the Eigen threshold. There is no mentioning of the 1,800 threshold, but there is a qualitative statement: "Indeed, we are unaware of translation being possible without the involvement of ribosomes, the complete sets of tRNA and aminoacyl-tRNA synthetases (aaRS), and (at least, for translation to occur at a reasonable rate and accuracy) several translation factors". They also discuss ID, irreducible complexity.
  3. Eugene V Koonin (2007) The cosmological model of eternal inflation and the transition from chance to biological evolution in the history of life, Biol Direct. 2007; 2: 15. (This is essentially Appendix B of the book)
  4. "The origin of life is one of the hardest problems in all of science, but it is also one of the most important. Origin-of-life research has evolved into a lively, interdisciplinary field, but other scientists often view it with skepticism and even derision. This attitude is understandable and, in a sense, perhaps justified, given the "dirty," rarely mentioned secret: Despite many interesting results to its credit, when judged by the straightforward criterion of reaching (or even approaching) the ultimate goal, the origin of life field is a failure–we still do not have even a plausible coherent model, let alone a validated scenario, for the emergence of life on Earth." (Koonin, p. 391).
    This text has been quoted by the uncommon descent intelligent design blog (Nov 13, 2011). The fact that the ID community is happy quoting Koonin without specifying a detailed ID alternative, demonstrates they are not interested in science, but only in attacking and ridiculing science. Why don't IDists want to know how the designer did it?
  5. "The probability of arriving at biologically significant arrangements is so very small that only by calling on the resources of the universe does there seem to be any possibility of life originating, a conclusion that requires on the Earth to be a minute component of a universal ssytem". From: Preface of: Fred Hoyle, Chandra Wickramasinghe (2000) Astronomical Origins of Life. Steps Towards Panspermia. [ 17 Dec 2013 ]

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Copyright ©G. Korthof First published: 3 Jan 2013 Updated: 3 Jan 2013 F.R./N: 21 Dec 2013