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Lee Spetner replies: All the random mutations I discussed in my book "Not by Chance" , (and by extension, all known mutations whose molecular structures have been examined) cannot serve as prototypes for the mutations that are supposed to make up the long series of evolutionary steps claimed by neo-Darwinists to have led to major evolutionary advances. They cannot serve as prototypes of the mutations in the steps that are supposed to have led from a single cell to an insect, from a fish to a mammal, and so on. Most of these mutations are single-nucleotide substitutions that disable a control gene. Disabling a gene cannot be a recipe for evolutionary advance. Although sometimes, perhaps, a gene would have to be disabled in the course of evolving a new enzyme, such disabling cannot represent a major portion of what has to occur to achieve a new function. It cannot even represent a small fraction of what must occur. Most mutations in a putative series of evolutionary steps leading to a new species or a new order, class, or phylum, must add to the genome the information necessary to achieve that advance. It should be clear that information must be added to the genome to evolve a bacterium into a human, or even into a fruit fly. One who insists that it is not obvious that a human genome contains vastly more information than that of a bacterium is a sophist.

If no mutation that has been studied is of the type needed for neo-Darwinian macroevolution, then there is no molecular evidence that random mutations and natural selection can achieve that evolution. Sure, we know many single-nucleotide substitutions that can lead to microevolution. But there is no argument about microevolution. My argument is against the premise that random mutation, even with the help of natural selection, is the driving force behind an evolutionary advance from a primitive cell to human beings. There is no genetic evidence for such a premise.

I submit that one need not measure the information in a gene to know if a particular mutation has added or subtracted information. There is no general way of measuring the information in a single message without relating it to the ensemble of messages from which it was chosen. Similarly, there is no general way of measuring the entropy in a single message without relating it to the ensemble of messages of which it is a member. Shannon was careful to avoid relating the information measure he was defining to the meaning contained in a message. The communication engineer must build a communication channel that will faithfully transmit a message regardless of how much meaning the customer attaches to that message.

There is no adequate definition of the information in a message without relating it to the ensemble of messages that could have been sent. Thus I cannot expect to measure the information in an arbitrary paragraph of English text. Nor can I expect to measure the information in a section of a genome. But whatever the information in a paragraph of text, if I struck out one or more sentences, I can be sure that I have not increased the information. Rather, I can confidently say that I have decreased the information. (I exclude the case in which the paragraph was nonsense and didn't contain any information to begin with. In such a case the information was zero both before and after I struck out the sentences.) This example shows that indeed one can sometimes determine whether a change in a message has decreased the information without having quantified the information of the original message.

I hold that the disabling of a genetic function is a decrease in information. Disabling a repressor gene is a decrease of information. It's like striking out a sentence in a paragraph. The strikeout might be improve the readability of the text, but it is not an addition of information. Certainly, one cannot write a book by starting with a few paragraphs and blue-penciling them. One might improve those paragraphs (analogous to microevolution), but one could never produce a book that way (analogous to macroevolution). This analogy applies to mutations like the disabling of a repressor gene (which can cause the overproduction of an enzyme) or degrading the specificity of an enzyme (which could increase the enzyme's activity on some other substrate), even though such mutations might be beneficial under special circumstances.

Neo-Darwinian macroevolution is supposed to proceed by getting rare lucky mutations, one after another, each installed in the population by natural selection. Single isolated adaptive mutations of the types that have been found are not sufficient. Eventually some real information has to be added to achieve macroevolution. The classic scenario of the neo-Darwinist is to duplicate a gene and then have it evolve without losing the function of the original gene. The duplicate might first lose some of its function, but then it has to build up something new. To use our example of reducing the specificity of the gene, it might be beneficial first to reduce specificity so as to grant the enzyme some activity on a new substrate. But that can be only the beginning. The second job is to have random mutations increase the specificity of the enzyme for the new substrate. The first is easy and can be done quickly. The second is much harder, and we have no evidence that it has ever occurred, in spite of the necessity for orders of magnitude more of this kind of mutation than for those of the type that disable a gene.

______________________________________________________ Ó 2010 Arthur V. Chadwick, Ph.D.