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The CRISPR Revolution: A Timeline of Discovery and Innovation
The Early Clues (1993 - 2005)
1993:
Francisco Mojica, a researcher at the University of Alicante in Spain, characterizes what is now known as a CRISPR locus. He identifies repeat sequences that share common features and coins the term “CRISPR.” These sequences match snippets from bacteriophage genomes, leading Mojica to hypothesize that CRISPR is an adaptive immune system1.
2005:
Alexander Bolotin discovers the Cas9 gene in Streptococcus thermophilus. Cas9, a nuclease, plays a crucial role in CRISPR-mediated genome editing. Bolotin’s work highlights the importance of the protospacer adjacent motif (PAM) sequence, required for target recognition1.
The Hypothetical Scheme
2006:
Eugene Koonin proposes a hypothetical scheme for CRISPR cascades as a bacterial immune system. He abandons the previous idea that Cas proteins might be part of a novel DNA repair system. Instead, Koonin suggests that CRISPR systems are based on inserts homologous to phage DNA in the natural spacer array1.
