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Reprogrammed Bacterium Speaks New Language of Life
wabrandsma writes "New Scientist reports that '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 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. ... The three combinations left over, UAG, UAA and UGA, act like a full stop or period – telling the ribosome to terminate the process at that point. ... A team of synthetic biologists led by Farren Isaacs at Yale University have now fundamentally rewritten these rules (abstract). They took Escherichia coli cells and replaced all of their UAG stop codons with UAAs. They also deleted the instructions for making the release factor that usually binds to UAG, rendering UAG meaningless. Next they set about assigning UAG a new meaning, by designing molecules called tRNAs and accompanying enzymes that would attach an unnatural amino acid – fed to the cell – whenever they spotted this codon."
>Although there are 64 ways of combining four letters
4*4*4*4 = 256
eh?
I should use this sig to advertise my book ISBN-13 : 978-1501515132.
I would approve of requiring labeling on food if it was produced by one of these.
Cool as hell, but I'm curious as to, well... why? And has anyone thought this through?
Okay, sounds alarmist, I know. That said, we're rapidly approachind a level in genetics where one fuckup in procedure or policy can have some really ugly repercussions. Not necessarily Resident Evil-scale ones, but possibly something fairly ugly in its own right.
Quo usque tandem abutere, Nimbus, patientia nostra?
Now I'm going to have to learn to program in DNA, and learn base 4. Thanks, biology! Oh well, I guess I'll probably get an anime cat-girl out of the bargain, so I'm not THAT pissed off.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
They are creating alien life, with the potential for organisms based on alternatives to the standard set of amino acids. I have no idea what all the implications of that will be.
This program was made possible by a grant from the Ultra-Humanite, and viewers like you.
Sheesz people, we've been rprogramming trna to use nonnatural amino acides for over 10 years now! Theres even a few companies st up that do just that. The principle of trna modification is old, just their method is new
If an experiment works, something has gone wrong.
Does this mean geneticists just figured out how to overclock cells?
No. Just added custom instruction set.
I get tired of having to repeat this warning every time this idea is rediscovered, but those are NOT wasted codons, and this scheme could hardly fail to cause catastrophic consequences if it gets into the wild. Over the years people have been discovering there is less and less 'junk' DNA, and everything in the code has a meaning. The stop codons are in all probability different. and someone is going to say 'oops' in a few years, when we wipe out all or part of life on earth.
If I wrote a computer program to do this, it wouldn't be special. If I submitted an article to slashdot that described how I wrote a C++ program to do this, I would probably get hate mail and possible death threats by some techie loon somewhere in Texas. Why is this story special simply b/c the process was done in a different environment? If this was a story about a new technique to manipulate codon sequences, that would be one thing. But it is not.
I had an overwhelming sense of dread when I read this (I never studied biology). Are we like like a bunch of five year olds playing with a loaded gun?
The Russians have won. They have made the world a cesspool of distrust, greed, fear and hate.
I'm still looking for one via á vis programming.
Btw., last time I communicated with a bacterium
it drove me crazy singing "it;s a small world
after all". A drop of chlorine set me free.
What could possibly go wrong?
Shoes for Industry. Shoes for the Dead.
So we're busy creating successors for ourselves after we're done killing off our species and most others through global warming.
After all, it's not like we'll to worry about being around to compete with these new life forms.
We've already pretty much doomed ourselves, and we're not doing anything to even slow down the heat-death, much less correct the problem.
I do not fail; I succeed at finding out what does not work.
Some years ago, when Venter's synthetic genome bacteria was created, I came up with a plan to do this on a more extensive scale.
(1) Sequence the genome of a bacterium, and edit the genome (on computer) to use no codons ending in 'T" or "A". (The redundancy of the genetic code allows this.)
(2) Also edit genome so that it has tRNA for the codons ending T or A which entirely change their meanings (but still using the standard amino acids.) (Transfer RNA - tRNA - are the mechanism by which the codon code is decyphered to amino acids.)
(3) Synthesize the edited genome, and replace the genome of a living bacterium with it. Breed for a few generations, to check that all is well, and to eliminate any of the old tRNA.
(4) Edit the genome to use entirely the new codons. Also edit replacement tRNA for the remaining codons, ending G or C.
(5) Replace the genome of one of our modified bacteria with this one.
Result: a bacterium which has an entirely rewritten genetic code, and is incapable of reading the old code.
However, I don't think I was the first to think this all up. In any case, Science didn't accept my letter proposing it.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Well, if you only had one of them, you would only have a very tiny bit of Turing himself.
Well, his mommy had only that much at one point. Fortunately, it was capable of self replication :P
I'm quite sure that, some day, these things will be labeling us as food...
How very right you are, considering these things are bacteria (see: Decomposition).
I've read a lot of articles about "reprogrammed bacteria," and until this article it's never really felt 100% appropriate until this article.
It seems to me that the redundancy in the code allows some triplets to be more stable than others. A random change from one letter to another shouldn't be a problem as long as the new triplet codes the same amino acid. In this light I would expect very important pieces of DNA to be coded in a way that allows more variability without changing function. How or if evolution deals with this would be interesting to study.
I've heard the speculation that because most (but not all) the redunant codons use just the first two letters of the three and ignore the third letter. This suggests an earlier 2-letter system coding for 15 amino acids and a stop.
I guess long ago some otpimum fitness was achieve agt three letters instead of two or four, maybe based in chemical complexitity and energety use.