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 The advance, reported on Wednesday in Nature, offers what one
scientist calls a "genetic firewall" to achieve biocontainment, a
means of insuring that GMOs cannot live outside a lab or other
confined environment.
Although the two labs accomplished this in bacteria, "there is no
fundamental barrier" to applying the technique to plants and
animals, Harvard Medical School biologist George Church, who led one
of the studies, told reporters. "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 biofuels, cleaning
up toxic waste, and manufacturing drugs.
Microbes are already used for those applications. In some cases they
contain genes from an unrelated organism, making them "genetically
engineered" or "genetically modified" to, say, gobble up oil spills
or produce insulin. But widespread use of such GMOs has been
constrained by concerns they could escape into the wild and do
damage.
In 2013, Church's team announced they had leaped beyond genetic
engineering to create "genomically recoded" organisms. Recoding
means that one bit of their DNA codes for an amino acid (a
building-block of proteins) different from what the identical DNA
codes for in every other living thing. The biologists had rewritten
the genetic spelling book.
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 manmade amino acid and require synthetic amino acids to
survive.
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Because the amino acids do not exist in nature, said Isaacs, now at
Yale University, the resulting "firewall" 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 calculated.
By pairing genomic recoding with this firewall, biologists could
create escape-proof microbes which, by incorporating novel amino
acids, could produce entirely new types of drugs and polymers,
Church said.
(Reporting by Sharon Begley; editing by Gunna Dickson)
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