James Tour Video Series on the Origin of Life — Assembly of Cellular Components
In my last two articles (here, here), I described how Rice University chemist James Tour, in his video series about the origin of life, elucidated the challenges associated with synthesizing life’s building blocks and linking them together properly to form macromolecules such as proteins, RNA, and DNA. Today, I will describe how Dr. Tour detailed the implausibility of a functional cell emerging even if all of the components were locally available. Claims to the contrary represent almost pure hype (here, here). This challenge has been compared to that of someone with absolutely no understanding of transportation vehicles assembling automobile parts scattered across the planet into a functional car without directions, tools, or an auto shop. The inherent difficulty is amplified by Dr. Tour’s mantra, “Molecules don’t care about life.”
The penultimate video addresses the central obstacle that the molecules in a cell can be interconnected in a fantastically large number of configurations, but only an infinitesimally small percentage of those configurations correspond to a functional cell. The number of configurations for just the possible interactions of proteins in a yeast cell was estimated by biologists Peter Tompa and George Rose to be on the order of 10 to the power of 79 billion. That number is a 1 with 79 billion zeros behind it! For a minimally complex cell, the number might drop to something closer to 10 to the power of a billion, but that figure is still unfathomably large. For comparison the number of particles in the visible universe is 10 to the power of 80.
The authors presented the implications with great clarity,
Consequently, it is implausible that a completely ‘‘denatured’’ cell could be reversibly renatured spontaneously, like a protein. Instead, new cells are generated by the division of pre-existing cells, an unbroken chain of renewal tracking back through contingent conditions and evolving responses to the origin of life on the prebiotic earth. We surmise that this non-deterministic temporal continuum could not be reconstructed de novo under present conditions.
The assembly problem would be just as great at any location at any time in earth’s history, and this problem at least matches the seemingly insurmountable problems previously described.
Minimally Complex Cell
The video also addresses the question of the requirements of the simplest possible cell. A minimally complex cell would still require at over 200 genes corresponding to hundreds of thousands of bits of information. The required amount of information is so great that 23 academics actually published an article suggesting that life could not have originated on earth. The authors state,
The transformation of an ensemble of appropriately chosen biological monomers (e.g. amino acids, nucleotides) into a primitive living cell capable of further evolution appears to require overcoming an information hurdle of superastronomical proportions, an event that could not have happened within the time frame of the Earth except, we believe, as a miracle (Hoyle and Wickramasinghe, 1981, 1982, 2000). All laboratory experiments attempting to simulate such an event have so far led to dismal failure (Deamer, 2011; Walker and Wickramasinghe, 2015).
Dr. Tour concludes his series with a call to researchers to fundamentally change the way they approach the problem of life’s origin. The current approach is completely misguided since it does not address such fundamental issues as the isolation of relevant molecules, the mass transfer problem, the origin of information, and the genesis of the interactome. I suspect this challenge will not be widely heeded for one simple reason. Carefully studying these issues will lead researchers toward a conclusion they simply are not willing to accept. Life is not the product of undirected physical processes, but it is the creation of an intelligent designer.
Dr. Tour has chosen to operate entirely within the rules of the academy, so he did not address the design hypothesis. Yet, in an earlier interview he did allow me to answer the question of what positive evidence points to design in a minimally complex cell, and he allowed me to describe how this framework best drives productive biological research. Based on this evidence, I would invite researchers to consider reaching beyond the confines of the academy and to follow the evidence where it truly leads.