June 29, 2009 | David F. Coppedge

How Cells Proofread DNA Is Still Mysterious

An amazing fact about DNA transcription is that the machinery not only copies DNA onto RNA, but checks it for errors.  A story in Science Daily says that researchers would expect 100 times more errors statistically than the actual results of transcription in the cell.
    One of the mechanisms revealed in more detail by researchers at University of Bristol and University of Leeds is a linear stalling process akin to an old-style typesetting machine.  DNA “letters” are transcribed single-file by a machine called RNA polymerase.  When a wrong letter is inserted in the RNA transcript, the machine stalls and backs up.  It then has a tiny “molecular scissors” that snips out the incorrect nucleotide and inserts the correct one.
    This is only part of the proofreading process, however.  The article ended, “there is more than one identified mechanism for ensuring that genetic code is copied correctly.  The challenge now is to find out – through a combination of experimental biology and modelling – which mechanism is dominant.”  One can expect that their analogy to a typesetting machine will develop over time into something more sophisticated: perhaps an office full of specialists using computerized error correction technologies.

Stephen Meyer’s new book Signature in the Cell (see Resource of the Week) explains why these discoveries are undermining evolution at its base.  In chapter two, he recounts the history of discoveries about DNA.  It reads like a detective story.  Since the mid-19th century, biologists and chemists tried to understand what was going on in the cell, then in the nucleus, then in the chromosomes, then in the bands within the chromosomes, then in the nucleic acids and their bases, then in the structure of the double helix.  It took a century to uncover the answer.  The reality turned out to be far more astonishing than anything they could have imagined.  In Darwin’s day, who would have thought that the cell has computer codes that are transcribed and translated, and proofread with multiple levels of error correction?
    Evolutionists have few options for responding to these discoveries.  One method they use is to say, “Well, if these mechanisms weren’t there, we wouldn’t be here.”  How satisfying is that?  If the universe weren’t finely tuned for life, we wouldn’t be here.  If life had not emerged, we wouldn’t be here.  If complex life had not emerged, we wouldn’t be here.  If DNA proofreading didn’t exist, we wouldn’t be here.  That’s not an answer; it’s a dodge.  If sensible people weren’t so tolerant of the Darwinists and their nonsense, they wouldn’t be here.

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