Emergence of Genetic Code Touted
Most origin-of-life researchers have acknowledged the extreme improbability of the genetic code arising by chance. Their approaches to get around this problem have varied considerably since the Miller experiment succeeded in generating a few amino acids. Despite the celebrations that 1953 experiment generated (05/02/2003), it did not even begin to approach the problem of solving the origin of the code that stores and directs the information of life. Can that problem be swept away by a bombastic title from a press release? Rockefeller University sent this up the flagpole: “Model Suggests How Life’s Code Emerged From Primordial Soup.” Science Daily then dutifully distributed the claim with no critique.
The press release began by acknowledging that the Miller experiment did not solve the problem of the origin of the genetic code. The basis of their claim is that the chemical or physical properties of RNA molecules make a code inevitable. Jean Lehmann said, “All these molecules have different properties and these properties define their interactions. What are the constraints that allow these molecules to self-organize into a code? We can play with that.” Lehmann did not consider whether it would be appropriate for a critic to play with different rules: e.g., defining the constraints that prohibit molecules from self-organizing into a code.”
Nevertheless, by playing according to the pro-evolutionary rules, the research team decided that transfer-RNAs (tRNA) were not as finicky about the molecules they associated with back in the primordial soup age. Using intelligent design, they “developed an algorithm to incrementally change the concentration of each molecule. Their goal was to see which conditions, if any, could coax the system to specifically translate codons in a nonrandom fashion.” In short, they wanted to coax the right amino acids to associate with the right transfer-RNAs.
Why molecules would want to do such things, or who would wish to reward them if they did, they did not say. They just wanted to present a theoretical framework, with a little bit of experimental support, to get “one step closer to understanding how life first began.” They did not state the criteria for measuring whether the step actually gets them closer or farther. Their paper, published in PLoS One,1 mentioned some things the press release glossed over: e.g., tRNA binding occurs with the help of a family of enzymes that associate the genetic code with the protein code: “A major issue about the origin of the genetic system is to understand how coding rules were generated before the appearance of a family of coded enzymes, the aminoacyl-tRNA synthetases.” For more on that problem, search on “synthetase” in the search bar above (e.g., 06/09/2003, 05/26/2004, 01/31/2007, bullet 3). They apparently thought that if a loose translation already existed, the synthetase enzymes would “emerge” in due course. For all this, their paper did nothing to explain how the information in the genetic code emerged; their system could do no better than to translate genetic gibberish. In the paper’s Discussion section, they said, “Although the molecular organization of genetic code is now known in detail, there is still no agreement on the reason(s) for which it has emerged.” After that, they acknowledged the chicken-and-egg problem: “Although these facts are fundamental, and have inspired scenarios for the evolution and the expansion of the code, evolutionary considerations may not, in essence, provide an answer to the origin of the code (since it is a prerequisite for biological evolution).” They realize that natural selection cannot be invoked before replication – and replication requires an accurate code. Here’s the last part of the paper:
In conclusion, our results show that the properties of amino acids and RNA can naturally impose a partially coded polymerization along RNA templates. We also found that the associated coding mechanism is remarkably robust against mismatches. When supplied with “meaningful” RNA sequences, translation systems of this kind should be capable of generating pools of proteins a small fraction of which will be functional. The feed-back action of these proteins on the translation itself may further increase its efficiency, allowing more codons to be added to its repertoire. In this evolutionary perspective, it can be speculated that a critical effect of emerging synthetases will be to establish only the [amino acid � tRNA] configurations that are fit for translation, a “learning” action that RNA alone cannot logically achieve.
1. Lehmann, Cibils and Libchaber, “Emergence of a Code in the Polymerization of Amino Acids along RNA Templates,” Public Library of Science One, 4(6): e5773; doi:10.1371/journal.pone.0005773.
OK, CEH volunteer police, time to take Apollos the Baloney Detector Dog and round up some more suspects (09/30/2007 commentary). These guys are not only charged with impersonating a scientist, but committing thought crime by being willfully ignorant and selling their ignorance publicly as science. Round up Science Daily as accomplices. Suggested sentence: watching Unlocking the Mystery of Life and reading Signature in the Cell. Public vagrancy at Rockefeller University is against the law. Ignorance is no excuse.