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Frankenstein's monster |
Let’s
look at one of the latest experiments in synthetic biology: George Church and
Nili Ostrov, Harvard biologists, are trying to build a strain of the bacterium Escherichia
coli immune to all existing viruses. How? By changing
its genetic code so that viruses do not understand it and cannot
use the bacterial cellular machinery to reproduce. Since the genetic code is
redundant, it is possible to replace one of the codons encoding the amino acid
arginine (AGA) with another that also encodes the same amino acid (CGC), and
all the genes of the bacterium would go on generating the same proteins. This
would be done with several rare codons. But since viruses would continue to use
the substituted codons, the bacterial cell machinery would no longer be able to
understand the DNA of the virus. This part of the job is almost finished. When
it is done, it would also be necessary to eliminate the transfer RNAs of the
missing codons and ensure that they are not remanufactured, so that the
cellular machinery can no longer use them.
Note
that the work done so far is the manipulation of the data recorded in the DNA.
It is equivalent to changing the information contained in the hard disk of a
computer so that it stops using a certain instruction of the language of the
machine, by replacing it with another equivalent instruction. We
are still very far from synthetic biology in the strict sense. Will it
be possible to synthesize life in the near
future?