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Originally posted by ChaseNelson:
Information is information--look up the definition in any dictionary. It can take on several forms--one form as the thoughts form in my brain, another as I type them, and yet another as I print them out on paper.
Actually I rather doubt that you will find a formalized and applicable (to biology that is) definition of information in a dictionary. And that is what you are apparently being asked for.
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Describe how all of the precise conditions required by proteins and DNA were met in the past and somehow allowed the evolution of DNA by random processes, 3) Explain how genetic information arose in the past (i.e., how mutations can add information to the genome)
First the precise conditions for the initial generation of DNA and proteins are not germane to evolution and also not to the evolution of information within living organisms. As to the increase in information that deals with populations as well as the organism (populations evolve, not individuals). Work by Sitiram, Rao and Witten (references are at home, I will try to add them later but they are in the J. of Theoretical Biology) demonstrates info increase at the gene level. The key thing that has neither been proven nor disproven by anyone is increase in information in the evolutionary sense. One of your citations is by Lee Spetner, in his one refereed paper on the subject (also in the J. of Theoretical Biology) he admitted that he was unable to address this point due to current limitations in information theory as well as in problems with the complexity of the system.
I have one additional comment, concerning the statements by Meyers that you cited. First, there are statistical correlations between groupings of amino acids and their associated tRNA's and the sequences that they bind to (ie the codons). Second, Meyers treatment of the DNA/Protein coding question is inappropriate in that he is treating it as an isolated system. To say that there is no STRICTLY chemical basis for the sequencing of any strand of DNA is accurate, as far as it goes. It completely leaves out the question concerning other physical effects as well as the system effects. For example, RNA has been demonstrated to polymerize and propagate on clay, mineral or silicate matrixes. The propogation of these sequences is actually a kinetic event where certian free forming sequences propogate faster than others. This "information" is passed down to the daughter strands. An interesting aside is that it is in the realm of kinetics that the left vs right hand issue appears to be solved, namely homogeneous strands propogate faster than heterogeneous strands, probably due to the increased stability of stacking within the homogeneous strands. Also, changes to a pre-existing code (ie mutations) result in a chemical change (ie the mutated protein). That protein may be better, worse or just different from the original protein. Couple that with gene or full or partial chromosomal duplication, an event which has been shown to occur, and you get a variety of information changes that account for the raw material which plays a role in evolution. To the best of my knowledge there is no real analogy in any other system described by info theory.
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"Chance favors the prepared mind." L. Pasteur
Taz
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