Creation Bits

Hit upon this post as well, thought I'd share. This post is about the informational content of DNA.

The Shannon-Weaver General Model of Communication (1947) proposed that all communication must include six elements:

* a source
* an encoder
* a message
* a channel
* a decoder
* a receiver

According to in Warren Weaver's introduction to Shannon's paper:

The word information, in this theory, is used in a special sense that must not be confused with its ordinary usage. In particular information must not be confused with meaning.

In fact, two messages, one of which is heavily loaded with meaning and the other of which is pure nonsense, can be exactly equivalent, from the present viewpoint, as regards information.

You tap on a membrane suspended above a steadily flowing jet of water. The air under the membrane causes slight deflections in the jet of water. A laser is aimed at a receiver. The jet of water flows through the laser beam, deflecting it from its target. Every time the water jet is deflected by the movement of the air, the laser beam hits its target. The laser receiver is connected to a computer which takes each 'hit' and turns it into a 1 and each miss and turns it into a 0. The computer sends these etc. etc......

You get the idea: the air waves, the jet of water and so on are all channels. The words channel and medium are often used interchangeably, if slightly inaccurately. The choice (a pretty stupid one above) of the appropriate channel is a vitally important choice in communication. It's obvious that you don't use the visual channel to communicate with the blind or the auditory channel with the deaf, but there are more subtle considerations to be taken into account as well. A colleague of mine was clearly much more responsive to visual communication than I. To elucidate his arguments he would inevitably grab a pencil and a piece of paper and sketch out complex diagrams of his arguments. Though they may have help him to clarify his ideas, they merely served to confuse me, who would have preferred a verbal exposition. But that argument deteriorates into one of semantics and differentiating meaning from signal concerning the definition of information. According to the Shannon-Weaver model of communication, meaning is divorced from that of the existance of a signal for a message to exist.

Genes are sections of DNA that code for a defined biochemical function, usually the production of a protein. The structure of a protein determines its function. The sequence of bases in a given gene determines the structure of a protein. Thus the genetic code determines what proteins an organism can make and what those proteins can do.

mRNA (Messenger RNA) is used to relay information from a gene to the protein synthesis machinery in cells. mRNA is made by copying the sequence of a gene, with one subtle difference: thymine (T) in DNA is substituted by uracil (U) in mRNA. This allows cells to differentiate mRNA from DNA so that mRNA can be selectively degraded without destroying DNA.

Genetic code is a language that is used by living cells to convert information found in DNA into information needed to make proteins. A protein's structure, and therefore function, is determined by the sequence of amino acid subunits. The amino acid sequence of a protein is determined by the sequence of the gene encoding that protein. The "words" of the genetic code are called codons. Each codon consists of three adjacent bases in an mRNA molecule. Using combinations of A, U, C and G, there can be sixty four different three-base codons. There are only twenty amino acids that need to be coded for by these sixty four codons. This excess of codons is known as the redundancy of the genetic code. By allowing more than one codon to specify each amino acid, mutations can occur in the sequence of a gene without affecting the resulting protein.

To refer to a particular piece of DNA, a person in Detroit might write: AATTGCCTTTTAAAAA. This is a perfectly acceptable way of describing a piece of DNA. That code can then be sent via the internet to somebody in Tokyo, where someone with a machine called a DNA synthesizer could actually synthesize DNA from the information specified by AATTGCCTTTTAAAAA alone. Subsequently that specific DNA can be spliced into a gene of some bacteria and a particular protein can be manufactured. Your premise is demonstrably false.

Furthermore, your statement There is no more information in DNA than there is in a snowflake is woefully ignorant. You confuse information with entropy. Clearly the degree of randomness within that of a snowflake is less than that of liquid water. Suggesting that the entropy of DNA is equivalent to that of a snowflake is ridiculous. DNA in inert form can be crystalized and may have similar entropy to that of a snowflake, and if I vaporize that DNA crystal and then re-crystalize it, its entropy essentially remains unchanged (it will be no more or less ordered than its previous crystalized from). But you will never be able to synthesize a protein from that form of crystalized DNA material (as from its orginal deconstructed form), while the deconstructed fundamental components of the snowflake can recreate another, albeit disimiliar snowflake it still will be a snowflake. The former has to do with a fundamental degree of randomness, the latter has to do with the fundemental physical properties of its components. What differentiates functional DNA from its inert form is that of its organization. What evolution has not done is provide a suitable answer to whether or not random chance, time and natural processes are sufficient for the origin of the organization inherent in biological DNA.

Finally, using your syllogism, and one of the examples you cite in support of your positin, I can stipulate that there's no more information on that CD-ROM you say contains War & Peace, than that of a grain of salt. That's perfectly sound logic (Modus Tollens) but invalid.