Intelligent Design

Challenging half a century of fundamental assumptions about redundant codons

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The DNA code is made up of codons (3-letter words) derived from 64 different arrangements of bases linking the two DNA strands. Yet these 64 combinations code for only 20 amino acids and a stop signal. Thus, different codons are able to produce the same amino acid. The phenomenon is described as the genetic code having “redundancy”. In the early years of molecular biology, this redundancy was perceived as an evolutionary accident, unworthy of detailed research but fortunate because it meant that any damaging effects of point mutations were cushioned. However, the evidence has been accumulating that “redundancy” is a misleading word.

“Scientists have known about this redundancy for 50 years, but in recent years, as more and more genomes from creatures as diverse as domestic dogs to wild rice have been decoded, scientists have come to appreciate that not all redundant codons are equal. Many organisms have a clear preference for one type of codon over another, even though the end result is the same. This begged the question the new research answered: if redundant codons do the same thing, why would nature prefer one to the other?” (Source here)

New research into protein synthesis in bacteria has shone new light on these issues. “A hidden and never before recognized layer of information in the genetic code has been uncovered by a team of scientists” using a technique called ribosome profiling. This tool allows gene activity inside living cells to be monitored, including the speed with which proteins are made.

For more, go here.

4 Replies to “Challenging half a century of fundamental assumptions about redundant codons

  1. 1

    This is an extremely fascinating and important area of research. Apparently we have all been guilty of thinking there was a simple, uninteresting answer to the redundant codons question. Will be watching this closely in the coming years.

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    Joe says:

    Hi Eric-

    The following may interest you:

    The Price of Silent Mutations

    In the book “The Design of Life” they touch on silent mutations and why they could cause a difference (HT DaveScott).

  4. 4
    Mung says:

    The DNA code is made up of codons (3-letter words) derived from 64 different arrangements of bases linking the two DNA strands.

    I must say that I disagree. The code is not made up of anything physical at all.

    And the “words” are not derived from the bases.

    Stringing together a sequence of bases in DNA no more makes a “word” than does stringing together a sequence of letters of the English alphabet.

    And it certainly doesn’t create an encoding.

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