[ Originally published on May 10, 2014 ]
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A
team of researchers from TSRI
[The
Scripps Research Institute]
in La Jolla, California have
created a brand
new bacteria
based on a genetic structure that is nowhere to be found on
this planet.
According
to lead researcher Dr.
Floyd
Romesberg,
the feat involved artificially engineering a unique combination of
DNA
[Deoxyribonucleic
Acid] material
[a
combination that’s
not
found in any living creature]
and
inserting it into a living cell that usually contains only natural
combinations of DNA.
“Life
on Earth, in all [of]
its
diversity, is encoded by only two pairs of DNA
bases, A-T and C-G,”
explained Romesberg
in
an institute news release, adding:
“And
what we’ve made is an organism that stably contains
those two, plus a third, unnatural pair of bases. This shows
that other solutions to storing [genetic]
information are possible
and,
of course, takes us closer to an expanded-DNA biology that
will have many exciting applications, from new medicines to new kinds
of nano-technology.”
The product of more than 15
years of work, the current effort builds upon a proof-of-concept
study that was conducted in 2008. At that time, investigators showed
that hooking up natural and unnatural pairings of DNA was possible in
a test-tube setting.
The
next challenge was to replicate the process inside of
a
living cell. The cell chosen by the TSRI team was the common E.
coli bacterium,
and they inserted into it what they considered to be the best
unnatural DNA pairing that they could construct: a combination of 2
molecules called “dNaM
and d5SICS.”
[ ^ Molecular composition of dNaM-d5SICS. ]
After
creating and testing
300
variants, the
authors of the study finally achieved their goal: a
half-synthetic organism that, when continuously supplied with the
necessary molecular material, could replicate its unnatural self.
In effect, the bacteria have a genetic code of 6 letters, rather than 4, perhaps allowing them to make novel proteins that could function in a completely different way from those which are created naturally. This accomplishment may eventually lead to organisms that can make new medicines or industrial products that cells that contain only the natural genetic code cannot.
The scientists behind the work at TSRI have already formed a company, which uses this revolutionary technique in order to develop new antibiotics, vaccines and other products, though a lot more work needs to be done before this is concept is made practical.
The
work also gives some support to the concept that life can exist
elsewhere in the universe using genetic sequences
that are
different
from those here
on Earth.
“This
is the first time that you have had a living cell manage an alien
genetic alphabet,”
said Steven
A. Benner,
a researcher at the Foundation
for Applied Molecular Evolution
in Gainesville, Florida.
This
research is bound to raise safety concerns and questions about
whether or
not humans
are “playing
God.”
The new findings could intensify calls for greater regulation of this
budding field known as “Synthetic
Biology,”
which refers to
“both the design and fabrication of biological components and systems that don’t already exist in the natural world, and the re-design and
fabrication of existing biological systems.”
“The
arrival of this unprecedented ‘alien’ life form could, in time
have
far-reaching ethical, legal and regulatory implications,”
said
Jim
Thomas
of the ETC
Group,
a Canadian advocacy organization, adding:
“While
synthetic biologists invent new ways to monkey with the fundamentals
of life, governments haven’t even been able to cobble together
the basics of oversight, assessment or regulation for this surging
field.”
Dr.
Romesberg
dismissed concerns
that the organisms would run amok and cause harm, saying that the
technique was safe, since the synthetic nucleotides were being
intentionally
and carefully fed
to the bacteria. Should
the bacteria escape into the environment or enter someone’s body,
they would not be able to obtain the needed synthetic material and
would either die or revert to using only natural DNA.
“This
could never infect something,”
said Romesberg.
That is one
reason that the company he co-founded,
Synthorx,
is
looking at using
this
technique to grow viruses or bacteria which
can
be
used as live vaccines.
Upon
being introduced into a person’s bloodstream,
they would conceivably induce an immune response, but not be able to
reproduce.
AMBRX, a San Diego company that has filed to go public, is incorporating the
novel amino acids into certain proteins which
are used as drugs, in an effort to make
the drugs more potent in killing tumors
and
to
make treatments last longer in the bloodstream.
“It
took some clever problem-solving to get where they got,”
said
Eric
T. Kool,
a
professor
of chemistry at Stanford,
who is also doing research in the area, adding:
“It
is clear that the day is coming that we’ll have
stably-replicating unnatural
genetic structures.”
[Self-replicating nanobots? ...]
Stay
conscious my friends.
~
Merit Freeman
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