Ever since Thomas Nagel selected Signature in the Cell as one of 2009’s best books, the Times Literary Supplement has had a vigorous back and forth in its letters section. The last salvo published was by Loughborough University chemistry professor Stephen Fletcher. The response below was submitted by Stephen Meyer to TLS, but they opted not to publish it.
To the Editor
The Times Literary Supplement
Sir–I see that the Professor Stephen Fletcher has written yet another letter (TLS Letters, 3 February, 2010) attempting to refute the thesis of my book Signature in the Cell. This time he cites two recent experiments in an attempt to show the plausibility of the RNA world hypothesis as an explanation for the origin of the first life. He claims these experiments have rendered the case I make for the theory of intelligent design obsolete. If anything, they have done just the reverse.
To support his claim that scientific developments have “overtaken Meyer’s book,” Fletcher cites, first, a scientific study by chemists Matthew Powner, Béatrice Gerland and John Sutherland of the University of Manchester (Nature, Vol. 459, pp. 239–42). This study does partially address one, though only one, of the many outstanding difficulties associated with the RNA world scenario, the most popular current theory of the undirected chemical evolution of life. Starting with several simple chemical compounds, Powner and colleagues successfully synthesized a pyrimidine ribonucleotide, one of the building blocks of the RNA molecule.
Nevertheless, this work does nothing to address the much more acute problem of explaining how the nucleotide bases in DNA or RNA acquired their specific information-rich arrangements, which is the central topic of my book. In effect, the Powner study helps explain the origin of the “letters” in the genetic text, but not their specific arrangement into functional “words” or “sentences.”
Moreover, Powner and colleagues only partially addressed the problem of generating the constituent building blocks of RNA under plausible pre-biotic conditions. The problem, ironically, is their own skillful intervention. To ensure a biologically-relevant outcome, they had to intervene–repeatedly and intelligently–in their experiment: first, by selecting only the right-handed isomers of sugar that life requires; second, by purifying their reaction products at each step to prevent interfering cross-reactions; and third, by following a very precise procedure in which they carefully selected the reagents and choreographed the order in which they were introduced into the reaction series.
Thus, not only does this study not address the problem of getting nucleotide bases to arrange themselves into functionally-specified sequences, but the extent to which it does succeed in producing biologically-relevant chemical constituents of RNA actually illustrates the indispensable role of intelligence in generating such chemistry.
The second study that Fletcher cites illustrates this problem even more acutely.
This work, conducted by Tracey Lincoln and Gerald Joyce (Science, Vol. 323, pp.1, 229–32), ostensibly establishes the capacity of RNA to self-replicate, thereby rendering plausible one of the key steps in the RNA world scenario. Nevertheless, the “self-replicating” RNA molecules that Lincoln and Joyce construct are not capable of copying a template of genetic information from free standing nucleotides as the protein (polymerase) machinery does in actual cells. Instead, in Lincoln and Joyce’s experiment, a pre-synthesized specifically sequenced RNA molecule merely catalyzes the formation of a single chemical bond, thus fusing two other pre-synthesized partial RNA chains. Their version of ‘self-replication’ amounts to nothing more than joining two sequence specific pre-made halves together.
More significantly, Lincoln and Joyce themselves intelligently arranged the base sequences in these RNA chains. They generated the functionally-specific information that made even this limited form of replication possible. Thus, as I argue in Signature in the Cell, Lincoln and Joyce’s experiment not only demonstrates that even limited capacity for RNA self-replication depends upon information-rich RNA molecules, it also lends additional support to the hypothesis that intelligent design is the only known means by which functional information arises.
STEPHEN C. MEYER, Ph.D. Cantab
Author, Signature in the Cell
Senior Research Fellow, Discovery Institute
Seattle, Washington, U.S.A.