Channel Five, 7.30 pm, Tuesday 6th January
2004
A commentary by David J. Tyler
Harry Kroto is Professor of Chemistry at Sussex University and recipient of the Nobel Prize for his pioneering work on C60 fullerenes. His big question dealt with the origin of life. Evidences of life are present in the geologic record at 3.5 billion years, he said. Very simple single-celled life forms like bacteria were around at that time - but how did they originate?
Louis Pasteur was credited as being “one of science's greatest heroes”. His experiments put paid to the idea of spontaneous generation. Although Kroto describes Pasteur in this glowing way, he did not quote Pasteur as saying “the more I study nature, the more I stand amazed at the work of the Creator”. This hero was a man who respected what the Bible had to say on origins and, like many Christians before him, he anticipated that life could not spontaneously generate because God alone creates life. Undoubtedly, this insight contradicts the main thrust of what Kroto had to say in the programme.
The next explanation considered was that proposed by Svante Arrhenius. This is known as Panspermia, meaning that life was seeded from outer space. Kroto described this as a “perfectly respectable theory” but declared that there is no evidence to support it and that it avoids addressing the fascinating problem of how primordial molecules flickered into life in the first place.
With this introduction, we were directed to the discoveries of Stanley Miller, first published in 1953. This research student set out to recreate the atmosphere of the early earth as he understood it. He placed the gases hydrogen, methane and ammonia in a flask and simulated the water cycle. Spark discharges were used to represent electrical storms. All the reaction products were collected as a sludge. Significantly, he found amino acids, the building blocks of proteins. Without proteins, life would be impossible.
A further breakthrough came later in 1953 with Crick and Watson's discovery of the structure of DNA and the genetic code. This, says Kroto, “finally unlocked the secret of life”. (It was a major milestone in understanding living things, but most impartial commentators on this issue would point out that life continues to hold on tenaciously to its secrets!).
Kroto continued: “so where did the DNA come from?” Despite much research, origin of life theorists had to admit defeat in moving from amino acids to proteins to DNA. The leaps were unrealistically large - they “seemed totally impossible”.
However, could there be an intermediate stage? Was there a missing link between Miller's amino acids and DNA? Kroto pointed us to RNA as the chemical go-between. Was there an RNA world before the DNA world? If there was, there must be a way for RNA to replicate itself. The breakthrough came with Sidney Altman and Thomas Cech who received the Nobel Prize for their efforts. They found a special type of RNA that could be deemed to replicate. “They did chemistry. It is simple. It does solve the problem. Altman and Cech breathed life into the RNA World”.
But a further question arises: how did the RNA World originate?
This is a difficult problem! Ribose is the backbone of RNA but it is not produced by Miller-type experiments. This is where Kroto drew attention to carbon chemicals in interstellar space. There is a growing list of molecules that have been discovered (see note ). He has decided to rerun the experiments incorporating some of these interstellar materials. “It'll take a few months, but if we are successful, you'll be hearing about it!”
Finally, Kroto pointed us to hydrothermal vents at the mid-ocean ridges. Were these the places where the ingredients were all mixed together?
To conclude the programme, Kroto tried to communicate his personal sense of excitement at the research achievements. I really like the RNA World, he said. It is “really beautiful science”. Major advances are just around the corner. It is a great time to be a young scientist entering this field. “What I like most about it is that it is just chemistry”.
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The programme raises a number of very important issues that need to be tackled head on. The presentation implied that only a few details remain to be sorted out, but the reality is that every step in this explanation of life's origin can be challenged.
Take Miller's experiments: there is no evidence for a primordial atmosphere of hydrogen, methane and ammonia. The consensus view at the moment is that the atmosphere of the Earth would be the result of volcanic exhalation: with the main gases being carbon dioxide, nitrogen and water vapour. Furthermore, photodissociation of water vapour into hydrogen and oxygen (driven by ultra violet radiation from the sun) would have led to at least some oxygen in the atmosphere. With this mixture of gases, Miller's apparatus yields no amino acids at all.
Furthermore, research with Miller-type scenarios has led to stalemate as far as what happens to the amino acids. Proteins do not form from amino acids in a watery environment. There is no self-assembling process; always the trend is to dissociation and degradation. The primordial soup is both devoid of a factual foundation and it leads nowhere. Kroto's proposed experiments are worth doing, but my prediction is that they will not close the gaps in the story. As long ago as 1977, origin of life researchers Sidney Fox and Klaus Dose concluded: “The inference that Miller's synthesis does not have a geological relevance has become increasingly widespread”.
Moving on to the RNA World, there is no doubt that RNA is an amazing molecule that is capable of some remarkable chemistry. But it is fragile and easily destroyed. It needs living cells to make it and to protect it. According to biochemist Gerald Joyce, “you have to build straw man upon straw man to get to the point where RNA is a viable first biomolecule.” (Irion, 1998).
So Kroto is at least correct to flag up the problem and the need for a pre-RNA World. However, bridging the gap via the primordial soup enhanced by extra-terrestrial carbon-based molecules is a lost cause. We are as far from a coherent account of abiogenesis as we ever were.
There are also a few things worth noting regarding “simple” cells in the primeval Earth. Over the past few months, papers have been published giving evidence of photosynthesis at 3.7 billion years and also chemical signatures of eukaryotic cells at about 2.6 billion years. The details need not detain us, but suffice to point out that the word “simple” is no longer appropriate to describe what we are actually finding.
It is worthy of note that Harry Kroto is an enthusiastic humanist, keen to promote humanist values and perspectives in society. Consequently, he brings a philosophy of naturalism (or materialism) to his scientific work. This is why, for him, abiogenesis must be “just chemistry”. Nothing outside physics and chemistry can be allowed into his study of origins. Any thought that life has something to do with a Creator God is anathema. This mindset is not in the best interests of science. It closes up avenues of enquiry and rules out, a priori , any approaches to the problem that incorporate intelligent design.
There is a missing word in the discussions of all philosophical naturalists – the word information . The omission is apparent when Kroto speaks of the discovery of the structure of DNA as “the key to life itself”. This is a very blinkered view. DNA is a chemical carrier for a code. It is the information carried in the code that is of crucial importance. There are no physical or chemical laws that produce codes. What we are seeing here is evidence for a mind, because we not only have to consider storing the code, but also transmitting it and decoding it before it can ever make useful materials for the cell. Evidence for a designer is staring us in the face every time we look at the information systems in living things. The tragedy is that so many have adopted a philosophical stance that prevents them from seeing the reality.
There are indeed many exciting areas of research for young scientists. However, humanistic scientists and other advocates of philosophical naturalism are forcing science down a road that is losing sight of the real world. As Pasteur discovered many years ago, a science that gives God his rightful place as Creator is both intellectually satisfying and of great benefit to mankind and the world in which we live.
References
Fox, S.W. and Dose, K. 1977. Molecular evolution and the origin of life . Revised Edition. Marcel Dekker, New York. Pp. 43, 74-76.
Irion, R. 1998. RNA can't take the heat. Science , 279 , 1303.
Note on carbon molecules found in interstellar dust clouds
The list of molecules detected in space now totals 131 entries. Most of these are carbon-based. The most significant recent finding is of the simplest amino acid glycine (NH2CH2COOH). A review of these findings and a listing of the 131 molecules will be found in: Charnley, S., Ehrenfreund, P. and Kuan, Y-J. 2003. Molecules in space. Physics World , 16 (10), 35-38.
However, the discovery is said to have "caused quite a stir in the astronomical community" An insight into this controversy can be found entitled 'On Glycine in the ISM' , with the conclusion: "At the moment it appears as if the publication of these reported inconsistencies will not settle the dispute of the glycine detection. Therefore, we would recommend reports on the detection or non-detection of glycine to be taken with a grain of salt."
