Comment:

A friend directed me towards your site. I’ve been reading your articles on how life could not possibility come about spontaneously. I was wondering what your thoughts are on this.  When a new property of RNA was discovered: some kinds of RNA can catalyze chemical reactions – and that means that RNA can both store genetic information and cause the chemical reactions necessary to copy itself. This breakthrough tentatively solved the chicken and egg problem: nucleic acids (and specifically, RNA) came first – and later on, life switched to DNA-based inheritance. This has solved the chicken and the egg dilemma and could also be a starting point for us explaining the origins or life. I look forward to your reply.

Response:

The RNA world is a hypothesis with essentially zero evidence supporting it. The quality of the hypothesis should be considered carefully. We should also bear in mind where and from whom the hypothesis is coming from.

First of all, for the naturalist/scientific materialist, there is no alternative. In other words, they are philosophically (not scientifically) committed to finding a naturalistic, non-supernatural explanation of the origin of life. Therefore, they KNOW that there must be a solution to the seemingly impossible problem of nature simultaneously producing, at the same time and in the same place, both molecules which can transmit and maintain information and molecules which can actually perform chemical reactions. In all living things, the molecules which pass information from parent to offspring is DNA, while the molecules which do virtually all the chemical work of the cells are proteins. This is where the "chicken and egg" paradox arises.  Which came first in the prebiotic soup? Molecules with information (DNA) or molecules which can build molecules with information (proteins) and which are only built by that DNA information?

The recent breakthrough you describe is not all that recent any more. It came about 25 years ago by a scientist who I happen to know personally from my time at the University of Colorado, Boulder. Thomas Cech discovered that RNA, a molecule closely akin to DNA can, in very limited cases, act as a catalyst. The catalytic function in living things was thought to be completely limited to proteins before Cech’s work (for which he got the Nobel Prize). The RNA world hypothesis was thus proposed. The speculation is that in the very early history of the earth, only ONE category of molecule had to chemically "evolve."

Let us, for the moment, ignore the fact that chemical evolution of highly complex molecules is not a possible process. The idea is that in the prebiotic RNA world, the same molecules functioned both to do the catalyzing of the reactions and to carry the information for the molecules created by those reactions. There are at least three problems with this highly speculative hypothesis.

1. RNA is very poor at reliably carrying information. Unlike DNA, it does not function well as a template for passing information from one generation to the next. It does not spontaneously form into a large-scale double-helical structure. The subtle difference in the shape of ribose rather than deoxyribose-based nucleic acids causes this difference. There is no reliable way for RNA information to be reproduced except in very small pieces), nor is there any evidence that this can happen.

2. RNA is also very poor at catalyzing reactions. Unlike proteins, it CANNOT catalyze a fantastically wide variety of chemical reactions such as acid/base, oxidation-reduction, hydrolysis, condensation and other reactions. It is a very poor candidate as a molecule which could conduct the chemical reactions in a living thing. There is no evidence that it could take on this function. I am not exaggerating when I make this claim.

3. Here is the worst problem for the RNA world hypothesis. There is no evidence for it. You can bet that scientists have searched for some remnant information which would support the idea that in the deep past of the earth, there were chemical systems which depended highly on RNA rather than DNA or protein. So far, as far as I have seen, there is literally no evidence for this.

So, where did this hypothesis come from? When first proposed it was a good scientific hypothesis.  I believe that this has now changed.  In my opinion, at this point it comes from people trying to rescue the completely materialist/determinist theory of abiogenesis. Or to put it more carefully, 20-25 years ago, when the ribozyme activity was first discovered (ie that RNA can have catalytic properties) the RNA world was an interesting hypothesis with some promise. However, now, 20-25 years later, with no concrete results for this model–with an extremely limited capacity for catalytic properties and no evidence for extended double helix formation, the RNA world hypothesis is looking to be very weak. It is now supported principally because it can, in principle, solve the problem of abiogenesis, not because it is a good scientific hypothesis.

The RNA world hypothesis did NOT solve the chicken-and-egg conundrum for the spontaneous origin of life, despite the claims of its supporters.

John Oakes