Prebiotic Nonstarters by Neil English

Origin-of-Life Scientists Fail to Meet James Tour’s 60-Day Challenge

Over the last few years, I have watched the meteoric rise of Dr. James Tour, the noted synthetic organic chemist based at Rice University who has single-handedly called the origin-of-life research community to account with his devastating critique of their laboratory methods and their grossly exaggerated claims about how relevant their research is given the conditions now understood to have existed on the early earth.

Earlier this year, Tour exposed the emptiness of claims made by YouTuber Dave Farina, aka “Professor Dave,” in a debate at Rice University during which “Professor” Dave could only respond to Tour’s searching questions with personal insults. (As we have covered in Salvo before, this is a rhetorical foul known as the ad hominem logical fallacy.)

After this first public debate, Tour was emboldened to ratchet the stakes up a notch by announcing a 60-day challenge to ten leading minds in the field of prebiotic chemistry. Tour invited researchers to answer any one of the following questions:

Can you prepare the dipeptide DK or KD (D = aspartic acid and K= lysine) to the exclusion of sidechain-linked systems using prebiotically relevant chemistry with a yield greater than or equal to 90 percent? (Many amino acids can hook up in different ways, but only particular linkages produce biologically active structures. The questions as to how the right linkages can come about blindly in a plausible prebiotic environment has not been answered.)

Can you polymerize more than 200 nucleotides in the biologically relevant linkage using prebiotically relevant chemistry? (Just like amino acids, nucleotides need to be able to hook up in the right way, but there are many ways the system can grind to a halt if the wrong linkages are made.)

Can you prepare the disaccharide from glucose by linking them in the biologically relevant way to the exclusion of other linkages i.e. regioisomers, using prebiotically relevant chemistry? (Sugars have an enormous number of structural forms, but only particular ones are biologically relevant.)

Can you account for the origin of the specified information embedded in the sequences in large biomolecules such as polypeptides, polynucleotides and polysaccharides?

Given all the resources (i.e., the basic building block chemicals) in pure form, how would you go about building a cell from those materials?

The ten scientists (all professors) he contacted were Clemens Richert (University of Stuttgart), Bruce Lipschutz (University of California Santa–Barbara), Jack Szostak (University of Chicago), Nicholas Hud (Geogia Tech), Lee Cronin (University of Glasgow), John Sutherland (MRC Laboratory of Molecular Biology), Matthew Poyner (University College London), Neal Devaraj (University of California San Diego), Steve Benner (University of Florida), and Ramanarayanan Krishnamurthy (Scripps Research Institute, California). Tour promised that if any of these researchers could answer just one of these questions, he would take down all his critiques of prebiotic research from YouTube and elsewhere. Furthermore, he promised not to ever discuss prebiotic research again. In addition, he appointed some of the above scientists as referees for his 60-day challenge.

A Nothing Burger

You need not concern yourself with the technical details of the above questions posed by Dr. Tour because after the 60 days had elapsed, he announced that no one had come forward with workable solutions.

Steve Benner, who’s based at the University of Florida, did write back, stating that had he been given all of the pure chemicals, as offered by Tour, he would be able to explain it all away, whereupon Tour invited Benner to meet with him to provide the solutions. Benner declined however, citing poor health and lack of time. The reality though, I suspect, is that he had no real answers to any of Tour’s questions. As Tour pointed out, Benner simply ducked the questions he raised.

The only individual from the ten who bothered to respond was Lee Cronin from the University of Glasgow, who said that Tour’s questions were, in his words, “too narrow” and “irrelevant.” That’s quite a statement to make. Cronin is well known for dodging such questions, however, and his approach involves other chemical systems that mimic some of the features of living systems, but that use chemicals that are not found in biology. Tour has already questioned the relevance of Cronin’s approach and has noted that Cronin bragged on a TED Talk back in 2011 that he would be able to create life in the lab in three years. Well, we are now 12 years out, and nothing has come of that claim, so I wouldn’t hold my breath!

However, Cronin did agree to have a debate with Tour at Harvard University. The debate is scheduled for November 28, so stay tuned.

Raising the Stakes

But Tour has a lot more up his sleeve. These are just five of the most basic questions that have not been answered; he has identified dozens of others that need to be answered. These include but are not limited to: the origin of the homochiral (properly oriented) amino acids and sugars needed to construct the biomolecules, the problem of supplying the fresh materials needed to sustain such reactions, the problem of how the myriad non-covalent interactions needed to stabilize such structures arise, and the problem of explaining how the biological membranes with their asymmetrical lipid bilayers are assembled.

Cronin has at least now admitted that no one has built a cell from scratch and that there appear to be significant barriers to achieving this milestone due to the information in cells that is stored outside the DNA in the nucleus of the cell, such as that stored in the structure of membranes and other epigenetic sources of complex specified information. From what I can gather from Cronin’s research, he has taken an inorganic chemistry approach to mimicking some features of living systems, but there are legitimate doubts regarding their relevance to prebiotic chemistry.

Whatever the outcome of that up-and-coming debate, it will most certainly increase Tour’s stature in the field and raise awareness among more academics and lay people about the thorny scientific issues facing origin-of-life research. So, watch this space!

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