• Question: The structure of DNA appears to be intelligently designed, what are the implications?

    Asked by Olly to Christie, Dan, David, Dawn, Sian on 20 Jun 2016.
    • Photo: David Robertson

      David Robertson answered on 20 Jun 2016:

      Interesting question, with interesting underlying assumptions.

      To take the question at face value, the implication of your question is that there is a “Designer”. However you have already assumed this in the question so it doesn’t really get us any further forwards. A much more interesting question is what is the evidence for intelligent design and how can we test it as a theory.

      The essence of any scientific theory is that it can be tested and the tests can disprove the theory. A theory that cannot be disproved may be a fun idea, but it is not a scientific theory.

    • Photo: Dawn Lau

      Dawn Lau answered on 20 Jun 2016:

      This assumes that there is an intelligent creator – which you are entitled to believe. But I think there’s enough evidence to suggest that the structure of DNA arose through evolution, not intelligent design.

      Biologists have suggested that RNA (which, like DNA, can carry genetic information but is structurally less complex) arose before DNA. With billions of years of evolution behind us, it is likely that RNA formed spontaneously with the chemicals available on earth. DNA would have evolved as a more effective way of passing on genetic information. Here is an article that details some more evidence for the evolutionary side: https://www.newscientist.com/article/mg21528795-500-dna-could-have-existed-long-before-life-itself/

    • Photo: Christie Waddington

      Christie Waddington answered on 21 Jun 2016:

      Ignoring the intelligently-designed bit (my colleagues have addressed that nicely!), I can try and answer the question as to what implications of the DNA structure are.
      1. It is a simple molecule – how can four bases do so much? Until we knew the structure (Francis and Crick, 1953), we always thought it would be a complex molecule because it did such complex things. Despite knowing the structure, it still gave us no clue as to what it did!
      2. Chargoff’s rule – A always pairs with T, and C always pairs with G (A = adenine, T = thymine, C = cytosine, G = guanine). This is the most stable configuration, and enables the strands to be parallel. This is based on hydrogen bonds, as there are 2 bonds between A and T, and 3 bonds between C and G. So you couldn’t have A and G as the number of bonds wouldn’t match up!
      3. Sugar-Phosphate backbone – this is probably because DNA originally came about from RNA (called RNA hypothesis if you want to look it up!), which itself has a sugar-phosphate backbone. It acts as the structural framework of the DNA/RNA and gives it the helix shape. This backbone has a negative charge and is hydrophilic – this is kind of handy for keeping DNA in the nucleus!

    • Photo: Sian Thomas

      Sian Thomas answered on 21 Jun 2016:

      Which for me suggests that intelligent design and evolution can have the same outcome!

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