NEXT GENERATION GENOME EDITING TECHNOLOGIES Next-Generation-Genome-Editing-Technologies | Page 6

Science keeps on looking efficient tools than we have at a certain point of time and so CRISPR
was introduced to mankind. CRISPR/Cas9 nucleases have several advantages over ZNFs and
TALEN, such as target design simplicity, efficiency and multiplexed mutations.
HISTORY OF CRISPR
Clustered regularly interspaced short palindromic repeats; are part of prokaryotic gene and as
their name suggests they are short repetitive base sequences, which have an important role in
bacterial defense mechanism. They are not only vital to prokaryotic defense mechanism but
are also considered as well-established pillars of modern day gene editing. These repeats have
repeated themselves in history many times even when they were not fully understood:
1. In 1987, Yoshizumi Ishino of Osaka University accidently cloned a part of CRISPR together
with target gene of his interest, lap.
2. In 1993, while studying Mycobacterium tuberculosis, researchers in Netherlands published
two articles about a cluster of interrupted direct repeats. They exploited this discovery to
design a typing method known as Spoligotyping, which is used till today.
3. At the same time repeats showed themselves in archaeal species, Haloferax and Haloarcula .
The function was then studied by Francisco Mojica, at University of Alicante, Spain; who also
showed that transcription of these repeats was also possible.
4. Finally, in 2007, Barrangou and colleagues demonstrated that S. thermophilus can acquire
resistance against bacteriophage by inserting a genome fragment of infectious virus into its
CRISPR locus.