THE NEXT BIG STEPS FOR SCIENCEJ^ VCHAMARYby DR JV CHAMARY (@jvchamary)
Dr Chamary is a biologist and author of
50 Biology Ideas You Really Need to Know.T
he most powerful new technique
in molecular biology is the
CRISPR-Cas9 system – known
as ‘CRISPR’.
CRISPRs (Clustered Regularly
Interspaced Short Palindromic
Repeats) are sequences of DNA letters,
first discovered in E. coli in 1987. A
decade later, researchers revealed that
CRISPRs form part of an anti-viral
defence system used by bacteria a nd
other microbes: after a virus invades a
cell, enzymes cut and paste bits of the
viral genome between CRISPR
sequences in the cell’s DNA. This
leaves a genetic memory for an RNA
‘guide’ t hat a n enzy me called ‘Cas9’
uses to recognise and destroy viral
DNA, should an invader return. In
2012, bioengineers showed that the
RNA guide could be reprogrammed
to target any DNA sequence.
One of CR ISPR’s most usef ul
applications is gene therapy – to treat
or even cure a disease by correcting
a patient’s DNA. In traditional gene
therapy approaches, a vector such as
a harmless virus is used to deliver
a working gene to compensate for a
defective copy. This inserts new DNA
at a random location in the human
genome, whereas CRISPR can also
remove a person’s faulty gene at a
specific place. Researchers have
already used CRISPR to fix conditions
like inherited liver disease in mice.
Unlike most gene-editing
techniques, CRISPR is revolutionary
because the technology is precise. It’s
also quick, cheap and easy to use – so
simple that even amateurs can use it,
including so-called ‘biohackers’.
Biohacker labs around the world, such
as the London Biohackspace, might
one day use CRISPR editing for their
do-it-yourself biology projects.Playing safe
Anyone who tinkers with nature can
be accused of ‘playing God’. It’s
understandable that critics might
worry about amateurs meddling with
organisms they don’t understand. But
CRISPR is merely a tool – you still
have to have a n idea of what genes
you wa nt to tu r n on a nd off. Plus,
biohacking is limited by the resources
available to a typical DIY bio lab.A powerful DNA
editing techniqueCRISPR
Biohackspace director Ilya Levantis (far right) discussing future plans with artist Lena Asai (centre) and other members
Dr JV Chamary looks at a new molecular biology technique
GENE EDITING
Scientists design a ‘CRISPR’ made from
RNA. It includes a series of letters that
matches a unique DNA sequence within
an organism’s genome.The CRISPR molecule is attached to
‘Cas9’ (shown here in beige). This is
an enzyme that uses its RNA ‘guide’ to
recognise the target DNA sequence.The CRISPR-Cas9 tool cuts the strands
of the target DNA’s double helix, then
the cell’s repair machinery will fix the
damage – minus the old DNA sequence.The CRISPR technique can be used to
delete unwanted DNA, or to find and
replace a sequence by adding genetic
material – such as a new gene.1
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