A Cold Start to Life? A Critique of the Frozen RNA World Hypothesis Highlighted in Discover Magazine, Summer 2011
By John Feakes
Introduction
For centuries Christian apologists have maintained that only a Christian worldview can account for the intelligibility of human experience. It is Christianity which provides the necessary preconditions for knowledge. Atheism on the other hand seems to have irrationality written all over it. Consider what the atheist worldview entails by way of faith commitment:
1. Being from non-being (the universe evolved from literally nothing)
2. Life from non-life (Spontaneous generation)
3. Rationality from irrationality
4. Morality from non-morality
Clearly, these articles of faith contained in the atheist creed are not only counter-intuitive, but are continually and universally contradicted outright by everyday experience. These four rather bizarre faith commitments must surely invalidate atheistic worldviews as avenues through which life, rationality, and morality might be intelligently and adequately explained. Perhaps this is why atheist thinkers in the scientific and philosophical communities have sought to defend these articles of faith with renewed vigour.
This article is intended to rebut a recent feeble attempt to defend article of faith #2, namely, that non-living matter was arranged into a living system by purely naturalistic processes (i.e. unguided by intelligent agency).
The Frozen RNA World Hypothesis Explained
This hypothesis suggests that the earliest chemical evolutionary steps that occurred on earth did not take place in warm water, as had been maintained since the days of Darwin. Rather, this hypothesis suggests that these primordial chemical steps took place within the ice that had entombed the early earth.
Where’s The Evidence?
There are several lines of evidence that have been advanced to support this hypothesis:
1. A priori commitment to naturalism
2. Solar evolution models entail a frozen, ice-covered early earth
3. Observed ammonia and cyanide reactions in frozen conditions
1. A Priori Commitment to Naturalism
This is fact is absolutely crucial to the whole debate, which is why so many creationists harp on it so often. Evolution is a faith commitment made by people prior to any evaluation of the available empirical data. The data itself is filtered through this faith commitment. For instance, a fossil may be carefully examined in order to determine its weight, mass, chemical constituents and so forth. What cannot be directly observed in this way is its age or its place on the supposed evolutionary family tree. These kinds of things are interpretations of the fossil which flow out of a commitment to the evolution story. It is therefore incorrect to say that the scientific facts of the universe support the evolution story. The scientific facts of the universe may be interpreted by either worldview – evolution or creation – in a way which coheres with one’s overall faith commitments. In such a case, how can one determine which worldview is the correct one?
There are several lines of reasoning which may be discussed which lay outside the scope of this brief article.[1] One such line of reasoning that may be commented on would simply be to ask, which worldview makes sense of the scientific endeavour in the first place? Recall that to “do science” one must assume several things that simply cannot be verified by the scientific method itself. For instance, one must assume that natural processes proceed with general uniformity. One must also assume that sense data is generally reliable, that thoughts can be more or less valid, that humans generally have true beliefs and that we ought to report the results of our scientific investigations honestly. Such assumptions square very well with a commitment to the Christian worldview.[2] On atheism, such commitments are completely without foundation.[3]
Nevertheless, the discover article displays absolute faith in the evolution story when it reflects upon the research of Stanley Miller. Commenting upon the many chemical samples that Miller had frozen in his lab, the article reads on page 8:
“They were part of a meticulous effort to understand chemical reactions that must have unfolded over millennia on early earth.” [Emphasis mine]
The question that very few people want to even consider is, “Why must we believe that life evolved naturalistically on this planet?” The fact that many have chosen to embrace the evolution story as an article of faith must not be allowed to pressure the more thoughtful among us into blindly following their lead. We have every right to demand an appropriate reason for ejecting God from the pool of possible explanations for life on this planet. To my knowledge no such reason has been advanced.[4] When we consider that the assumptions necessary to carry out the scientific endeavour in the first place flow naturally out of Christian Theism, the exclusion of God as a possible explanation for life’s origins must surely appear absurd.
Absurd or not, a commitment to naturalism requires that life’s origins be explained purely in terms of chemical reactions unguided by intelligent intervention. Because cyanide and ammonia can react under frozen conditions to produce RNA building blocks, many secular scientists are convinced that life was launched naturalistically from such frozen beginnings. As will be discussed later in this article, the production of a few chemical building blocks is light-years from arranging matter into a living system. Undaunted, the scientists in the Discover article have opted to exclude God as a possible explanation and instead chose to embrace a secular creation myth in which centre stage is an ancient, frozen earth.
2. Solar evolution models entail a frozen, ice-covered early earth
The Discover article reads,
“According to standard solar evolution models, the sun was some 30 percent dimmer at that time, providing less heat to earth...our planet may have cooled to average temperature of -40oF, and a crust of ice as much as 1,000 feet thick may have covered the oceans.”
As water freezes, the molecules arrange themselves in a crystalline pattern in which contaminants are excluded. Apparently they are pushed to the grain boundaries where these chemicals – in this case cyanide and ammonia – are forced together were synthetic reactions can occur. Again, this is nowhere near anything like spontaneous generation.
The hero of the plot in this latest scenario is, as always, the sun. In this case, it was a decrease in solar output that encouraged the experiment of living some 4 billion years ago. The problem however is that the hero in this story also turns out to be the story’s greatest villain. Had the sun been producing 30% less heat than it does today (for the first 600 million years of its life, as the story goes), the earth would have become locked in a runaway deep freeze from which only the most extreme and implausible circumstances could have freed it. The sun simply evolving to its present state would not be enough because the earth’s then glary surface would have reflected much of the solar radiation back into space. In fact, to free the earth from such a deep freeze would require that the sun produce 27% more heat than it does today. Highly unlikely!
Several hypotheses have been advanced to overcome this “faint young sun problem” Most of these involve enormously high levels of greenhouse gas(es) in the earth’s early atmosphere. Of course this is all very ad hoc. There is not a shred of evidence to support any of this. Had earth’s atmosphere contained such vast amounts of heat trapping gas in the atmosphere, chemical traces of this ought to be found in the earth’s ancient rocks. To date such evidence remains elusive and the “faint young sun” problem remains unresolved.[5]
As expected, the Discover article doesn’t even address what appears to be a major problem in the whole evolution story.
3. Observed ammonia and cyanide reactions in frozen conditions
The article claims on p. 9:
“Freezing preserves fragile molecules, giving the time to accumulate and perhaps organize themselves into something more interesting – like life.”
The article continues on p. 10:
“Cyanide is a good candidate as a precursor molecule in the life-in-a-freezer model for several reasons. First, planetary scientists suspect that cyanide was abundant on early earth, deposited here by comets or created in the atmosphere by ultraviolet light or lightening (one the atmosphere became oxygen rich, 2.5 billion years ago, however, the process would have stopped). Second, cyanide has a convenient tendency to self-assemble into larger molecules. Third, and perhaps most important, no matter how much cyanide rained down, it could become concentrated only in a cold environment – not in warm coastal lagoons – because it evaporates more quickly than water.”
The article informs us further down that frozen cyanide in the presence of ammonia can produce a nucleobase called adenine. Of course this is very interesting but does nothing to show that the early earth really was frozen or that its atmosphere really once contained vast quantities of cyanide. Chemists know what chemicals react synthetically under various conditions and this knowledge is now being superimposed upon their view of the early earth. In short, scientists are proposing a frozen early earth rich in cyanide, not because the geological evidence actually supports such a proposal, but purely because the desired chemical reactions require such conditions.
On p. 11 the article describes one experiment where small amounts of nucleobases adenine, cytosine and guanine were mixed into artificial seawater and frozen for a year. The result was RNA molecules up to 400 bases long. Of course this sounds very impressive until we realize that the deck was loaded from the start (this is the language used in the article). It turns out, before the sample was frozen, a single-strand RNA template was added to the mixture to act as a guide in the formation of the new strand. The article states the obvious:
“But it’s the first step - the formation of the original RNA molecule-that remains a mystery.”
On pp.10-11 the article assures us that even without templates such experiments have created RNA strands up to 30 bases long. Researchers also noted that certain RNA enzymes behave strangely when cooled below freezing. For instance, one synthetic RNA enzyme designed to latch onto the hepatitis C virus, joined its ends into a circle, like a snake biting the end of its own tail. Similarly, the RNA molecule hairpin, which normal cuts RNA molecules into pieces, acted in reverse when frozen. That is, hairpin “glued” ends of RNA strands together.
The idea of course is that a molecule like hairpin actually evolved in this hypothetical frozen environment and began joining other evolved sections of RNA together. The article states that, “Freezing stabilizes the complexes formed from multiple pieces of RNA.”
An enquiring mind would want to know how many bases something like hairpin contains, and the article itself provides the answer. Hairpin’s normal length is 58 bases long – 28 bases longer than template-free experiments have apparently been able to produce. At this point the problem appears obvious. Hairpin is a stretch of RNA that is unlikely to have evolved in an unguided process – frozen or not. Without a molecule like hairpin to join the bases of evolved RNA, the credibility of the hypothesis becomes very strained indeed. For this reason researchers,
“...introduced random mutations into the hairpin RNA, shortened it from its normal length of 58 bases and even cut it into pieces, all in an effort to produce RNA enzymes that were as dodgy and imperfect as early earth’s first enzymes probably were. These pseudoprimitive RNA enzymes do nothing at room temperature, but freeze them and they become active, joining other RNA molecules at a slow but measurable rate...Equally telling, the pseudoprimitive RNA enzymes...grabbed and joined just about any other molecule. Enzymes on early earth might have done the same, joining random segments of 5 or 10 bases to form a variety of sequences.”
For a committed evolutionist, the temptation to speculate is irresistible. The article reads on pp. 12-13:
“On the young earth pockets of liquid could have expanded into a network of channels that mixed their contents during freeze-thaw cycles, like day-night temperature changes in summer. In winter, the liquid pores would contract and become isolated again, returning to their separate experiments. With all the mixing, something special might eventually have formed: an RNA molecule that made rough copies of itself. And as earth warmed, those molecules might have found a home in newly thawed seas or ponds, where something even more complex might have emerged – such as a cell-like membrane. ‘You have something that is multiplying itself, and you have variation that is inherited’, says Antonio Lazcano, a biology researcher and professor at the National Autonomous University of Mexico, In Mexico City. ‘There you have the onset of Darwinian evolution. I’m willing to call that living.’” [emphasis mine]
The whole imaginative scenario seems to hinge upon the availability of an RNA enzyme capable of joining small stretches of RNA together. The hairpin molecule, whose chemical properties under frozen conditions was already known, but whose spontaneous generation under plausible prebiotic conditions remains unobserved, was enlisted by scientists to fill the position. Though shortened (we are not told how many bases were required for this shortened version of hairpin to fulfill its pre-scripted task of joining RNA segments) the molecule itself was apparently deliberately altered to perform its assignment. What we are hearing about, it seems to me, is intelligent design, not an unguided evolutionary process.
It is also important to note that the scenario requires, once again, that the proposed chemical mixture somehow find its way into liquid water where further synthetic reactions can occur. The problems with such a scenario are well-known, which is no doubt why researchers find the “Frozen RNA World Hypothesis” so attractive. For example, water, it is well known, acts a depolymeriser. That is, water is an amazing solvent that normally breaks molecules apart rather than act as a vehicle through which synthetic reactions of the required type occur. In addition the article states on p. 12,
“Normally when an enzyme cuts an RNA chain in two, a water molecule is consumed in the process, and when two RNA chains are joined, a water molecule is expelled. By removing most of the liquid water, ice creates conditions that allow the RNA enzyme to work in just one direction, joining RNA chains.”
Recall that under frozen conditions, natural selection really has no part to play in favouring the production of enzymes which will be synthetic rather than destructive under normal conditions. The evolutionary scenario has lengths of RNA flowing into liquid water where some of these enzymes would have become destructive once again. When the RNA “soup” found its way into liquid water (when the earth somehow broke out of its deep freeze) we can expect that destructive enzymes would have gone to work hacking our newly evolved RNA molecules to pieces. In a watery environment, diffusion of this material once again becomes the obvious problem.
In addition, RNA is typically an unstable molecule, being susceptible to changes in CO2 and Ph levels for example. We must therefore imagine that all the right chemicals found their way into a pond someplace that enjoyed constant and favourable conditions over an extended period of time.
Lastly, this newly evolved genetic material would have to have become encapsulated in a membrane appropriate for protection from the environment in which replication could have taken place. Some have proposed that this material became entombed in something like a droplet of oil, which would indeed allow for the concentration and protection of RNA. The problem of course is that oil droplets disallow material from crossing into and out of the “cell.” Special channels in the membrane made up of protein must be present. [6] The problem here is that protein is coded for by genetic material and assembled by protein “machines” situated throughout the cell. We have a chicken and egg problem here of gargantuan proportions that the article simply glances over.
Conclusion:
The chemistry involved in RNA synthesis under frozen conditions is interesting but unconvincing as a naturalistic explanation for life’s origins. The hypothesis overlooks the faint young sun paradox, assumes a chemistry for earth’s early atmosphere unsupported by geology, and involves investigator interference to make appropriate and apparently essential RNA enzymes in order to produce the desired chemical effects. This in addition to the unlikely but essential mixing scenarios proposed in the article show that this whole “explanation” for life’s origins is in fact intellectually bankrupt. It looks more like a nature myth dressed up as science than a legitimate and intellectually satisfying account of life’s origins.
Notes and References
1. Truth claims may be evaluated based on the following criteria:
a. Is it coherent (does it contradict itself)?
b. Is there adequate empirical evidence?
c. Does it make sense of and cohere with my experience?
d. Is it affirmable?
e. Is it actually undeniable?
2. The Bible teaches that God created the universe and superintends the general uniformity natural processes (Genesis 8:22). Further the Bible teaches that human kind was created in God’s image with minds designed specifically to apprehend truth. In addition the Bible contains numerous injunctions to be truthful (Colossians 3:9). With these kinds of assumptions, a person is justified in engaging in legitimate and fruitful scientific investigation.
3. Roger Jones sums up the materialist account of history:
“The whole incredible big bang story with its climatic human ending is merely the result of physical and chemical processes that are completely random, accidental and meaningless.”
Roger S. Jones (Associate Prof. Of Physics, Universty of Minn.), “Physics for the Rest of Us”, Contemporary Books, Chicago 1992, p. 131
On this view one is hard put to justify a belief in the validity of thought, the uniformity of natural process, or the injunction to report one’s findings honestly. These are simply arbitrary faith commitments, given naturalistic presuppositions.
4. The oft-repeated claim that commitment to Christian Theism will halt scientific progress is a scare tactic devoid of truth. As noted above, Christian presuppositions provide the necessary reasons for engaging in the scientific endeavour in the first place. It is atheistic commitment that will undermine legitimate scientific progress.
5. “Despite all these proposed warming mechanisms, there are still reasons to think that the faint young sun problem is not yet solved.” James Kasting, Nature, “Faint Young Sun Redux”, 464, 2010, p. 688; “Challenges for each hypothesis remain, and are likely to remain for some time.” Alicia Newton, Nature Geoscience, “Warming the Early Earth”, 3, p. 458, 2010
6. For a critique of the RNA World Hypothesis, listen to the interview with Molecular Virologist Mark Williams HERE.
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