Table 2.
A brief history of major events in the field of CRISPR method.
| Year | Major Events in the Field of CRISPR Method | Refs |
|---|---|---|
| 1987 | Short direct repeats were first reported in the genome of the bacterium E. coli. | [18] |
| 2000 | Repetitive sequence that Ishino found in E. coli also was identified in other bacteria and archaea. | [19] |
| 2002 | -Proposal of CRISPR name and identification of cas gene. | [109,110] |
| -Discovery of transcript of CRISPR. | ||
| 2003 | The first reports of experimental identification of a protein associated with CRISPR DNA repeats. | [111] |
| 2005 | -Discovery of source of spacers from viral origin and plasmid. | [20] |
| -Proposal of idea in which CRISPR-Cas may be an adaptive defense system in bacteria. | [112] | |
| -Identification of protospacer-adjacent motif (PAM). | [113] | |
| 2007 | First experimental evidence for CRISPR adaptive immune system S. thermophilus. | [22] |
| 2008 | -Identification of mature CRISPRRNAs (crRNAs) as guides with Cas proteins complex as anti-phage defense system in E. coli. | [23] |
| -Studying the interference activity of Type III (Csm) CRISPR-Cas in Staphylococcus epidermidis. | [114] | |
| 2009 | -Investigating the antiviral activity of Pyrococcus furiosus by CRISPR-Cas systems. | [115] |
| -Identification of type III-B Cmr complex that cleaves ssRNA. | [116] | |
| 2010 | Identification of cleavage produced by the CRISPR/Cas bacterial immune system at three nucleotides ahead of the PAM sequence. | [117] |
| 2011 | -Classification of three major classes of CRISPR-Cas systems: types I, II, and III. | [11] |
| -Discovery of trans-activating CRISPR RNA (tracrRNA). | [118] | |
| -Applying the S. thermophilus type II CRISPR-Cas system in E. coli, reporting that the system is active in some distantly related organisms. | [119] | |
| -Discovery of “seed” sequence (the seed sequence or seed region is a conserved heptametrical sequence, which is mostly situated at positions 2–7 from the miRNA 5’-end). | [120] | |
| 2012 | -Adaptation of type II CRISPR system (originated from S. pyogenes) for gene editing in mammalian cells. | [121] |
| -First demonstration of programming CRISPR for targeted DNA cleavage in vitro. | [122] | |
| 2013 | -Using Cas9 successfully for genome editing in eukaryotic cell. | [123] |
| -Identification of the role of III-B system in transcription-dependent DNA interference. | [124,125] | |
| -First use of CRISPR-Cas system in plants. | [126] | |
| 2014 | Crystal structure of apo-Cas9, Cas, guide RNA, and target RNA. | [127,128] |
| 2015 | -Crystal structure of chimeric Cmr complex. | [129] |
| -CRISPR/Cas9 was utilized in human embryos. Researchers applied system to repair the HBB locus, which is responsible for β-thalassemia blood disorders when it is mutant. The experiment was not effective due to its off-target activities and impossibility of prediction of gene-editing outcomes through pre-implantation genetic diagnosis (PGD”) | [130] | |
| 2016 | -Cmr- and Csm-mediated RNA-activated DNA cleavage discovered | [24] |
| -The first human trial to apply CRISPR gene editing obtained approval from the NIH. | [131] | |
| -New approach to genome editing that requires no dsDNA cleavage or a donor template. | [24,132,133,134] | |
| 2017 | -Identification of a specific CRISPR protein that targets RNA rather than DNA. | [32] |
| -Developing an efficient version of the CRISPR-Cas9 system called CRISPR-Gold technology that utilizes gold nanoparticles to deliver the CRISPR/Cas9 gene-editing system to cells. | [135] | |
| -Identification of base editing. | [63] | |
| 2018 | Detected pre-existing antibodies that target Cas9 proteins. Represented the possibility of immune systems responses undermining the use of CRISPR-Cas9 for gene therapy. | [136] |
| 2019 | -Cas12a orthologs showed-editing capacity in human cells. | [137] |
| -BhCas12b was also engineered as a powerful gene-editing tool. | [138] | |
| -Many new subtypes of Type-V CRISPR system were identified. | [139] | |
| -Cas12k was found as an RNA-guided site-specific integration system in E. coli. | [140] | |
| -The Class-I CRISPR system with multiple effectors has been harnessed or using fused FokI domain. | [141,142] | |
| 2020 | -CRISPR-Cas12-based detection of SARS-CoV-2. | [143] |
| -Discovery of protein inhibitors of CRISPR-Cas systems, called anti-CRISPR (Acr) proteins. | [144] | |
| 2021 | -‘CRISPRoff’ CRISPR-based tool to switch off genes in human cells without making a single edit to the genetic code is described. | [145] |
| -FDA approves first trial investigating CRISPR gene editing as HIV cure. | [146] | |
| -CRISPR is used for molecular genetic control of insect vectors of virus diseases (sterile insect technique). | [147] | |
| -CRISPR enzyme’s ancestors reported in microbes | [148,149] |