Researchers make milestone GMO discovery

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New man-made bacteria may lead to improved containment of genetically modified plants

NEW YORK (Reuters) — Two teams of scientists have achieved another “synthetic biology” milestone, a year after creating organisms that use a genetic code different from every other living thing.


They have now created bacteria that cannot survive without a specific man-made chemical, which potentially overcomes a major obstacle to wider use of genetically modified organisms.


The advance, which was reported in Nature, offers what one scientist calls a “genetic fire wall” to achieve bio-containment, which is a way to insure that GMOs cannot live outside a lab or other confined environment.


The two labs accomplished this in bacteria, but “there is no fundamental barrier” to applying the technique to plants and animals, said Harvard Medical School biologist George Church, who led one of the studies.


“I think we are moving in (that) direction.”


If the technique succeeds, it could be used in microbes engineered for uses from the mundane to the exotic, such as producing yogurt and cheese, synthesizing industrial chemicals and biofuel, cleaning up toxic waste and manufacturing drugs.


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Microbes are already used for those applications, and in some cases they contain genes from an unrelated organism, which make them genetically modified. 


However, widespread use of such GMOs has been constrained by concerns they could escape into the wild and do damage.


Church’s team announced in 2013 that it had leaped beyond genetic modification to create “genomically recoded” organisms. 


Recoding means that one bit of an organism’s DNA codes for an amino acid differently than what the identical DNA codes for in every other living thing. 


The biologists had rewritten the genetic spelling book.


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In the new studies, teams led by Church and a former colleague, Farren Isaacs, created strains of E. coli bacteria that both contain DNA for a man-made amino acid and require synthetic amino acids to survive.


Isaacs, who now works at Yale University, said the amino acids do not exist in nature, which means any GMOs that escaped a lab, manufacturing facility or agricultural field would die.


Church’s team made 49 genetic changes to E. coli to make them dependent on the synthetic amino acid. The odds of a microbe undoing all the changes are astronomically high, he said.


Church said biologists could use genomic recoding and the new fire wall to create escape-proof microbes, which, by incorporating novel amino acids, could produce entirely new types of drugs and polymers.

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