- #1
Another God
Staff Emeritus
Gold Member
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This idea just struck me. I think it might be one of those ideas which could be revolutionary, but at the same time, it could also just as equally be a stupid idea which everyone who knows what they are talking about can instantly see as a waste of time and money and completely impractical/unimplementable.
Quick Background: DNA code is transcribed into mRNA, and those mRNA molecules are translated into Proteins according to the 'Universal Genetic Code' (which isn't completely universal) by tRNA's that are molecules which recognise codons in mRNA molecules. That is, according to a specific sequence in the tRNA (say AGC), it binds to the complementary RNA sequence (UCG) and adds the appropriate Amino Acid (Threonine) to the growing protein.
Implication of this: If you change anyone of the tRNA recognition sequences, then the way DNA is translated changes completely. Any organism which you did this to would become completely inviable since the decription process of the DNA program has changed completely. It would be like taking a book and randomly substituting every letter, every space and every punctuation mark with a new one (even if we shifted every symbol one to the right say, and A = B, B = C etc), and then expecting the book to make sense. Chances are, every now and then a meaningful; word might pop up or something, but the sentence structure would disappear completely and so nothing meaningful could be done with it.
The Idea:
We could construct tRNA's so that all of the 64 possible codons are accounted for, accounted for in the same ratio, with a similar degree of efficiency of translation (this is important), but nonetheless slightly different. We could design this (probably through trial and error), and we could then get the genetic code for ..say...Wheat, and alter the code so that the mRNA molecules are the sequence required to produce the normal protein products, in light of our new tRNA's.
In theory, the pant would produce the same proteins, the outcome would be the same, but the coding would be different.
Why do this?
Because one of the 'threats' associated with GMOs, is their escaping into the natural habitat. The chance of the actual plant itself escaping is effectively zero because our farm plants are selected to be great at providing food for us, not great at surviving (thats why 'weeds' kill our plants so easy...'weeds' are great at surviving). The threat comes from the fact that the pollen from the GMO's may accidentally cross pollinate into related wild plants, and those plants may in turn gain an advantage and out compete other wild plants.
Another threat is the fear that the plant could cross pollinate into 'organic' plants of the same species in a nearby organic farm.
By changing the tRNA's of GMO's, there is no chance of cross pollinating: The genetic codes are completely different. Any living organism could not use the DNA of these GMO's because it is meaningless to them. It uses a different language.
Problems
AS i said at the start, this idea only just occurred to me. So now that I have written it out, a whole onslaught of problems have occurred to me.
changing the tRNA's is easy, but DNA does more than encode mRNA for codon translation...I am not sure how changing the DNA RE Codons might affect other signals imbedded in the DNA. Many promoter sequences and repressor binding sites are inside the DNA code of Genes...so by changing the code, we also change the expression rates inadvertantly.
Also, doing this would actually mean re-engineeringn whole plants from scratch basically, and while this is sort of theoretically possible...Its not practical at all. I mean, its a few years worth of solid work from many many people no doubt. But then, the same thing was the case for the Human Genome Project... (Point in case: it toook how many years for them to 'sequence' a genome, let alone reconstruct one!)
Anyway, yeah, play with that. Monique and Ian, tell me if there are any more problems with it that I didn't consider.
Quick Background: DNA code is transcribed into mRNA, and those mRNA molecules are translated into Proteins according to the 'Universal Genetic Code' (which isn't completely universal) by tRNA's that are molecules which recognise codons in mRNA molecules. That is, according to a specific sequence in the tRNA (say AGC), it binds to the complementary RNA sequence (UCG) and adds the appropriate Amino Acid (Threonine) to the growing protein.
Implication of this: If you change anyone of the tRNA recognition sequences, then the way DNA is translated changes completely. Any organism which you did this to would become completely inviable since the decription process of the DNA program has changed completely. It would be like taking a book and randomly substituting every letter, every space and every punctuation mark with a new one (even if we shifted every symbol one to the right say, and A = B, B = C etc), and then expecting the book to make sense. Chances are, every now and then a meaningful; word might pop up or something, but the sentence structure would disappear completely and so nothing meaningful could be done with it.
The Idea:
We could construct tRNA's so that all of the 64 possible codons are accounted for, accounted for in the same ratio, with a similar degree of efficiency of translation (this is important), but nonetheless slightly different. We could design this (probably through trial and error), and we could then get the genetic code for ..say...Wheat, and alter the code so that the mRNA molecules are the sequence required to produce the normal protein products, in light of our new tRNA's.
In theory, the pant would produce the same proteins, the outcome would be the same, but the coding would be different.
Why do this?
Because one of the 'threats' associated with GMOs, is their escaping into the natural habitat. The chance of the actual plant itself escaping is effectively zero because our farm plants are selected to be great at providing food for us, not great at surviving (thats why 'weeds' kill our plants so easy...'weeds' are great at surviving). The threat comes from the fact that the pollen from the GMO's may accidentally cross pollinate into related wild plants, and those plants may in turn gain an advantage and out compete other wild plants.
Another threat is the fear that the plant could cross pollinate into 'organic' plants of the same species in a nearby organic farm.
By changing the tRNA's of GMO's, there is no chance of cross pollinating: The genetic codes are completely different. Any living organism could not use the DNA of these GMO's because it is meaningless to them. It uses a different language.
Problems
AS i said at the start, this idea only just occurred to me. So now that I have written it out, a whole onslaught of problems have occurred to me.
changing the tRNA's is easy, but DNA does more than encode mRNA for codon translation...I am not sure how changing the DNA RE Codons might affect other signals imbedded in the DNA. Many promoter sequences and repressor binding sites are inside the DNA code of Genes...so by changing the code, we also change the expression rates inadvertantly.
Also, doing this would actually mean re-engineeringn whole plants from scratch basically, and while this is sort of theoretically possible...Its not practical at all. I mean, its a few years worth of solid work from many many people no doubt. But then, the same thing was the case for the Human Genome Project... (Point in case: it toook how many years for them to 'sequence' a genome, let alone reconstruct one!)
Anyway, yeah, play with that. Monique and Ian, tell me if there are any more problems with it that I didn't consider.