| Creation Truth Outreach, Inc. Pamphlet |
| © 2007 Creation Truth Outreach, Inc. All Rights Reserved. This pamphlet may be freely copied provided it is copied in its entirety, its contents are not altered in any manner, and additional or tighter copyright restrictions than these are not imposed on it. Revised May 5, 2008 |
| Chapter 3. Sixteen Fatal Roadblocks against a Purely Natural Formation of Life. Fatal Roadblock Number 10. Origin Of Genetic Code (Arbitrary Selection). Where did the genetic code come from? The code is simply an abstract sequence of information bits placed into the DNA. At a conceptual level, it is very similar in structure and function to the storage of information bits on a computer’s disk drive. (Author’s note: I worked as a design engineer in Silicon Valley for over two decades. At one point in my career, I was a staff engineer at National Semiconductor Corporation. My responsibilities included the electronic design specification for a disk drive controller chip. This controller determined where on a disk to place segment identification information, start bits, stop bits, and the actual information to be stored in the various information segments (sectors) of a disk drive. Concerning the disk information, there were several available coding formats to store the data, known as FM, MFM, and run-length limited. The controller could write and read the data using any of these formats. I am awed by the similarity in the high-level structure between disk drive storage formats and the genetic code, which also has identification sequences, 13 start bits, stop bits, and a particular format for storing blocks of information.) Notice, the manner in which information is stored in a disk drive—that is, the use of block identifiers, start bits, stop bits, and a reduction of abstract information into strings of data bits— represents and is the product of years of progressive effort by many different design engineers. It is the product of applied intelligence. When I see how many of these same characteristics have been implemented in the structure of the genetic code and the format in which it stores information, to me the parallel strongly implies that the genetic code is also the work of an intelligent designer. The genetic code is based on tiny segments of information called codons. A codon consists of three sequential nucleotide bases. There are four bases available for use in a codon. The sequence of bases defines the stored information content. In RNA, the bases are represented by the letters C, G, A, and U. These letters represent the molecules cytosine, guanine, adenine, and uracil. The structure of DNA and RNA is such that a living cell has available an elaborate mechanism capable of extracting the information contained in a sequence of bases. The three sequential bases in a codon, with four possibilities per position, give a total of 64 possible codons. The following chart shows the relationship between nucleotide base sequence and codon function. Except for start and stop bits, all names represent a specific amino acid defined by the nucleotide base sequence of the codon. The Genetic Code AAA lysine ACA threonine GAA glutamic acid GCA alanine AAG lysine ACG threonine GAG glutamic acid GCG alanine AAC asparagine ACC threonine GAC aspartic acid GCU alanine AAU asparagine ACU threonine GAU aspartic acid GCU alanine AGA arginine AUA isoleucine GGA glycine GUA valine AGG arginine AUG start bit GGG glycine GUG valine AGC serine AUC isoleucine GGC glycine GUC valine AGU serine AUU isoleucine GGU glycine GUU valine CAA glycine CCA proline UAA stop bit UCA serine CAG glycine CCG proline UAG stop bit UCG serine CAC histidine CCC proline UAC tyrosine UCC serine CAU histidine CCU proline UAU tyrosine UCU serine CGA arginine CUA leucine UGA stop bit UUA leucine CGG arginine CUG leucine UGG tryptophan UUG leucine CGC arginine CUC leucine UGC cysteine UUC phenylalanine CGU arginine CUA leucine UGU cysteine UUU phenylalanine In life, it really does not matter what the code assignment is, except that it needs to be consistent. Any one assignment would work about as well as any other. There is a reason for this. Implementation of the code takes place in certain kinds of molecules called transfer RNA. It is the structure of the transfer RNA molecule that makes definition of the genetic code arbitrary. Transfer RNA molecules consist of two parts. At one end of the molecule there is the proper chemical structure to recognize a particular codon triplet in RNA. Let’s call this end the triplet recognizer. The other end of the molecule has the proper chemical structure to select for a particular amino acid. Let’s call this end the amino acid selector. The important thing is that the various triplet recognizers and amino acid selectors connect to each other in an identical manner. Hence, it is arbitrary concerning which triplet recognizer is associated with which amino acid selector. There is no particular advantage of any one association over another. Yet, it is the choice of association that determines the definition of the genetic code. By simply rearranging which triplet recognizers are connected to which amino acid selectors, the code definition could easily be changed. There needs to be a survival difference between choices in order for natural selection to choose between the best of the two or more alternatives. Yet, we saw that assignment of amino acid codon sequences is arbitrary, there is not any particular advantage of any one choice over any other. Natural selection is ineffective in choosing between equivalent alternatives. When a design engineer is faced with a set of equivalent choices to implement a particular feature in the course of working out a design, which is a normal, frequent situation, he simply makes an arbitrary decision to use one of the choices and moves on with the design. Since selection in this case is arbitrary, I have coined the term “arbitrary selection” to describe it. Natural selection cannot perform arbitrary selection because there is no difference in survival value between the alternatives. The identifier bits used by the genetic control mechanism to identify the location of various genes represents another case of arbitrary selection. Normally, the specific choice of identifier bits is not important. However, certain things are critical. 1. The bit pattern must be unique. It must actually be capable of identifying a required gene sequence. 2. The various patterns must be properly embedded at the correct location within the stored information. 3. A control system to use these bits is needed. All three of these items must appear from the very beginning with absolute consistency. Random mutation and natural selection cannot meet these three requirements, because they represent specific assignment. Yet, an intelligent designer would find the task trivial. Stephen Jay Gould said that if natural selection did not offer an adequate mechanism to account for the development and creation of everything we see in the various forms of life we see around us today, then evolutionary theory is dead.14 Well, evolutionary theory is dead |