The CRISPR Sequences

The CRISPR sequences were first discovered in 1987 when scientists were studying a gene that is involved with Alkaline Phosphatase Isozyme Conversion in Escherichia coli. It was not until 2007 that they came to understand that it was an acquired bacterial immune system that fight against the intrusion of a foreign nucleic acids such as viral genes and plasmids. To understand how the CRISPR system works, scientist employed the use of bacteria Streptococcus thermophilus in their experiment. Several strains of S. thermophilus were grown at a bacterial condition, 37 degrees in LM17 medium. The strains of bacteria were exposed and infected with purified bacteriophages to see if external DNA can be integrated into the bacterial genome. Furthermore,
Cas genes which code for polymerases, nucleases and helicases were disorganised to understand their roles.