Scientists create 'genetic firewall' for new forms of life
Scientists create 'genetic firewall' for new forms of
life
By Sharon Begley 8 hours ago
NEW YORK (Reuters) - A year after creating organisms that
use a genetic code different from every other living thing, two teams of
scientists have achieved another "synthetic biology" milestone: They
created bacteria that cannot survive without a specific manmade chemical,
potentially overcoming a major obstacle to wider use of genetically modified
organisms (GMOs).
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.
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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