Discovery of the CRISPR Gene Editing System
                        CRISPR players
1987 - Yoshizuma Ishiro observes repetitive DNA sequences in E. coli & later in Archaean species.

1992 - Franciso Mojica analyzes these repeats & coins term CRISPR 'clustered regularly interspaced palindromic repeats'

2002 - the DNA repeats are shown to occur near CAS nuclease genes that can unwind & cut dsDNA 

next -  DNA sequencing showed that the repeats came from bacteriophage DNA, likley by infection & integration

2007 - P. Hovrath & R. Barrangou of yogurt producer Danisco studying bacteriophage infections of yogurt
           bacteria showed infections added new viral spacer DNA & their removal affected ability of yogurt bacteria
           to resist infections. The viral DNA made RNA pieces that guided CAS nucleases to attack the invading
           DNA and cut it up... 'a kind of bacterial immune system providing resistance to viral infections'.
           CRISPR sequenes have subsequently been found throughout microbial life systems.

2008 - 1st CRISPR conference @ Berkeley and speculation grows that the bacterial CRISPR system might be
           used to not only target viral DNA for cutting, but any DNA with a "guide sequence".  



2011 - a. the essentials of how CRISPR works in bacteria are known and Emmanuelle Charpentier identifies an
               essential RNA component 'tracrRNA of unknown function.
           b. Eva Nogales, Doudna's colleague describes crystalline structure of the molecules
           c. V. Siksnys (Vilnius U.) identifies a CAS-9 nuclease as the enzyme that cuts DNA
           d. Jennifer Diudna & Emmanuelle Charpentier meet at conference in Puerto Rico and begin a collaboration

2012 - Dounda & Charpentier publish in Science that the system requires 2 RNA structures to have Cas9 make
           double strand cuts, a guide crRNA and a tracrRNA, which can be combined in a single transcript to
           cleave any DNA target binding sequence with complementarity to a gene, offering a methodology based
           on RNA-programmed Cas9 (that has considerable potential for gene-targeted editing applications).           

2013 - Feng Zeng of Broad Institute showed that the Doudna methodology worked in mouse and human cells in
           culture. By end of 2013 Zeng's group had 64,571 unique CRISPR sequences for some 18,080 Human
           genes (80% of the Human genome) with a 50% to 80% effectiveness.

2020 - Jennifer Doudna and Emmanuelle are awarded the Nobel Prize in Chemistry for the development of a
           method for genome editing.

current - The CRISPR system is easy to use and editing can today be done in almost any lab. Even CRISPR Kits
               are available to edit genes. Addgene ("the Amazon for Plasmids") is a non-profit that distributes
               some 60,000 plasmids of various constructs (CRISPRs) to 20,000+ labs in 85 different countries for
               researchers to use.

               But, to date no CRISPR 'health' products to cure any illness are on the market. The US Patent Office
               has 6,000+ CRISPR patent applications pending.