Reprogrammed bacterium speaks new language of life

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A bacterium has had its genome recoded so that the standard language of life no longer applies. Instead, one of its words has been freed up to impart a different meaning, allowing the addition of genetic elements that don't exist in nature.

The work has been described as the first step towards a new biology because the techniques used should open the door to reinventing the meaning of several genetic words simultaneously, potentially creating new types of biomaterials and drugs.

The engineered bacteria, dubbed genetically recoded organisms (GROs), have the added advantage of being resistant to many existing viruses. They are also less likely to escape the lab and survive than conventional genetically modified organisms, which should make them more palatable for commercial use.

The four letters of the genetic code are usually read by a cell's protein-production machinery, the ribosome, in sets of three letters called codons. Each codon "word" provides instructions about which amino acid to add next to a growing peptide chain.

Although there are 64 ways of combining four letters, only 61 codons are used to encode the 20 amino acids found in nature. This means that some of the codons encode the same amino acid – a phenomenon called redundancy. 

Written By: Linda Geddes
continue to source article at newscientist.com

12 COMMENTS

  1. I cringe at such experiments. If such DNA gets into the environment, and it turns out that was not such a hot idea, there is no way to recall it. These things should be treated like experimenting with ebola. At least we know the consequences with ebola.

    • In reply to #1 by Roedy:

      I cringe at such experiments. If such DNA gets into the environment, and it turns out that was not such a hot idea, there is no way to recall it. These things should be treated like experimenting with ebola. At least we know the consequences with ebola.

      What’s there to cringe at? They aren’t using a new form of DNA they simply changed the meaning of one of the three stop codons which now codes for an amino acid that isn’t naturally found. Even if this were to pass to another bacterium that bacterium would simply read the UAG as a premature stop codon.

      • In reply to #2 by Mormon Atheist:

        In reply to #1 by Roedy:

        Every time I write a computer program, I can see no possible reason why it might behave differently that I expect, but oddly nearly always it does. With GMOs, even if there is only a very small chance of a screw up, there is no way to undo it if it has leaked into the environment. To me that requires levels of care taken to avoid accidental nuclear war.

        • In reply to #6 by Roedy:

          In reply to #2 by Mormon Atheist:

          In reply to #1 by Roedy:

          Every time I write a computer program, I can see no possible reason why it might behave differently that I expect, but oddly nearly always it does. With GMOs, even if there is only a very small chance of a screw up, there is no way to und…

          See but that is my point this isn’t an entirely untested program. The fact is they had to change a lot of things in that cell just to get it to work (i.e. inserting tRNA, replacing UAG stop codons w/ UAA, Inserting UAG into genes, etc.). And I am sure they are being careful although I can’t think of a scientific reason that would cause this to go wrong.

        • In reply to #6 by Roedy:

          Every time I write a computer program, I can see no possible reason why it might behave differently that I expect, but oddly nearly always it does. With GMOs, even if there is only a very small chance of a screw up, there is no way to unddo it if it has leaked into the environment. To me that requires levels of care taken to avoid accidental nuclear war.

          Again your analogy is flawed. Nuclear weapons are specificly made to destroy whole cities in an instant, and in mass, to destroy the whole world. So “handle with extreme care” is a no-brainer there. Yes, it would be stupid to run your untested program on live, unbacked up data. But how much testing is enough? And as someone else pointed out, even if you do let a buggy program out “into the wild” there is no realistic chance that it will somehow turn into a sentient AI (bent on human annihilation) or all-destroying virus. Bugs get through sometimes and cause occasional problems, we fix them. The benefits of software (and all technology) have always far outweighed the new problems they cause.

          The idea that GMO’s have the potential for destruction equivalent to nuclear weapons (or anywhere near it) is laughable on the face of it.

          Again, it bears repeating, in different ways, over&over in this kind of discussion: NATURE IS CREATING GMO’s ALL THE TIME.. randomly, in vast, vast numbers… and nature does not care one fig if it kills us all… so be afraid, be very very afraid

    • In reply to #1 by Roedy:

      I cringe at such experiments. If such DNA gets into the environment, and it turns out that was not such a hot idea, there is no way to recall it. These things should be treated like experimenting with ebola. At least we know the consequences with ebola.

      If you cringe at this, you should also cringe because nature is constantly experiementing with random mutations. Large swaths of your own cells are mutants of the genome of your original egg/sperm. Bacteria & viruses mutate at a ridiculous rate, in effect always trying something new. It is far more likely that nature will come up with something nasty than human researchers who are trying to make something benign. (researchers deliberately trying to invent some nasty germ-warfare disease might be another matter, however, but that is another question).

      The kind of basic research being done here is far more likely to lead to (or contribute to development of) treatments for nasty diseases(not to mention many other useful technologies) than to somehow by some bizarre chain of events lead to some nasty disease (or other environmental catastrophe).

  2. This is soooooooooooo cool. I wonder if we can actually claim that this constitutes creation? I am wrapping my head around it and it is fascinating to think that they were able to get an amino acyl-trna transferase to load an amino acid that is outside the 20 that are used by life. This is jaw dropping. The sheer number of things that they had to engineer and make perfect (in order for this to live) is mind boggling to me.

    • In reply to #5 by Roedy:

      I am a computer programmer. The one thing you never do is run a new untested program on your data without backing it up first.

      Have you ever heard of a company called Microsoft? Or something called ‘the games industry’? Most programmers I know are aware of the consequences of releasing untested code into the environment. Because it happens all the time, and it’s never been the end of the world; even 14 years ago. Worrying that GMO will make bananas that produce VX nerve gas is about as likely as an amateur programmer playing with code sections and accidentally producing a fully sapient AI. In the near term, we’re pretty limited in what we can do and what we can do deliberately.

      In a few decades time, when the kit and knowledge to do this might be available on ebay for under $1000, then I might be worried – but we’re not there yet.

    • In reply to #5 by Roedy:

      I am a computer programmer. The one thing you never do is run a new untested program on your data without backing it up first.

      GMO folk do the analog of this every day.

      I am also a computer programmer, but I can tell the difference between the fragility of computer programs vs. the robustness of biological systems.

      Using your own overly simplified analogy, nature is already “backed up”, ever organism is a backup of (most of) the gene pool of its species. Nature is highly redundant, and all species have vast tools for self-defense at both the macro & micro scales.

      And as I pointed out in my other reply, nature is far more likely to come up with something nasty via random mutations that happen all the time than humans who make intentional changes for benevolent research (again with the exception of humans deliberately trying to make something nasty — but even there, we must suppose that some government or terrorist group is going to to do this eventually, and we must therefore do research in order to defend ourselves from the kinds of things that might one day be engineered to kill us).

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