CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) came to the science scene in the late 1980s when Dr Yoshizum Ishino and colleagues discovered a palindromic (reads the same backwards and forwards) DNA sequence in E. coli bacteria. At this time, there was no previous knowledge of such sequence or indications of its functionality.
In the 1990s, Dr Francisco Mojica and colleagues came across the same phenomenon in archaea (essentially the ‘cousins of bacteria’ with different biochemistry). A third independent discovery by Jansen and colleagues identified CRISPR as unique to prokaryotes and not in eukaryotes or viruses.
In later years, Mojica discovered commonalities in the gene sequence from viruses and concluded that CRISPR sequences protect bacteria and archaea from viruses with the identical sequences - speculated as an evolutionary immunological adaptation. Essentially the DNA of contracted viruses into the CRISPR region of host DNA and allows them to be passed onto future generations. CRISPR is an in-built genomic record of vaccines that the species has contracted.
Dr Virginijus Šikšnys worked on transferring CRISPR into the test tube environment while Dr Emmanuelle Charpentier and Dr Jennifer Doudna worked on identifying the natural pathway of CRISPR and finding out how the sequence came to be. Charpentier and Doudna discovered CRISPR-Cas9, a genome with the ability to edit genes - specifically identifying viruses and cutting them out. Cas-9 could also be programmed to insert and delete specific parts of DNA sequence allowing precise changes in genetic sequences. The discovery of applications such as gene editing are continuously being explored. In 2013, Dr Feng Zhang’s lab published they had deciphered a way to effectively manipulate Cas9 in human cells.
CRISPR has great potential i.e. changing the genome of embryos and removing HIV virus from in-vitro human cells. This article barely scrapes the surface of the vast scope that is the future of CRISPR application both within and outside of synthetic biology. CRISPR is a revolutionary discovery that embodies the fact that science is at the forefront of change. Stay tuned for next week’s post, CRISPR: The Future, where we discuss the future of CRISPR and its potential to treat diseases such as sickle cell.
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By Tomi Akingbade, Founder