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Scientists have discovered a second code hiding within DNA

  1. Dec 12, 2013 #1
  2. jcsd
  3. Dec 12, 2013 #2

    Simon Bridge

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    Oh dear - I can just see the pseudoscience and creationism-stuff that will fall out of this article...

    "Since the genetic code was deciphered in the 1960s,..." um, was it?
    Deciphering a code usually implies that you know what it says.

    It gets worse. "information storage device" <sigh>

    The science seems fine though.
  4. Dec 12, 2013 #3


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    The authors themselves say that it is not a new phenomenon. The advances here seem to be estimates of how pervasive and conserved it is. They cite these as previous examples.

    The protooncogene c-jun contains an unusual estrogen-inducible enhancer within the coding sequence
    A transcriptional regulatory element in the coding sequence of the human Bcl-2 gene
    Transcriptional enhancers in protein-coding exons of vertebrate developmental genes
    Discovery and characterization of human exonic transcriptional regulatory elements
    Coding exons function as tissue-specific enhancers of nearby genes

    The new paper is
    Exonic Transcription Factor Binding Directs Codon Choice and Affects Protein Evolution
    Andrew B. Stergachis, Eric Haugen, Anthony Shafer, Wenqing Fu, Benjamin Vernot, Alex Reynolds, Anthony Raubitschek, Steven Ziegler, Emily M. LeProust, Joshua M. Akey, and John A. Stamatoyannopoulos

    Genomes contain both a genetic code specifying amino acids and a regulatory code specifying transcription factor (TF) recognition sequences. We used genomic deoxyribonuclease I footprinting to map nucleotide resolution TF occupancy across the human exome in 81 diverse cell types. We found that ~15% of human codons are dual-use codons (“duons”) that simultaneously specify both amino acids and TF recognition sites. Duons are highly conserved and have shaped protein evolution, and TF-imposed constraint appears to be a major driver of codon usage bias. Conversely, the regulatory code has been selectively depleted of TFs that recognize stop codons. More than 17% of single-nucleotide variants within duons directly alter TF binding. Pervasive dual encoding of amino acid and regulatory information appears to be a fundamental feature of genome evolution."
    Last edited: Dec 12, 2013
  5. Dec 13, 2013 #4


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    This is one of the most overblown stories I've read in a long time. I haven't read the original paper yet but it seems all they've discovered is that some regulatory sequences contain smaller sequences that would code for amino acids if they were exonic.
  6. Dec 13, 2013 #5


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    I think the media is just still on that "junk DNA is not junk!" tip.
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