Although CRISPR-Cas has found many uses in biotechnology and medicine, it originates in nature, where it functions as a microbial immune system.
Just as our immune system remembers the pathogens we have been exposed to earlier in life, CRISPR-Cas provides microorganisms with an ability to respond quickly to viruses they have previously encountered by storing a small amount of the viral DNA in their own genome.
CRISPR-Cas is found naturally in most bacteria as well as the so-called archaea. When examining the origin of life on Earth, archaea are particularly interesting, as they form a kind of 'missing link' between bacteria and the cells of higher eukaryotes like our own. Studies of these organisms can therefore provide us with important insights into how the CRISPR-Cas immune system has evolved over hundreds of millions of years.
New research sheds light on how CRISPR-Cas emerged early during the development of life on Earth, as well as how this immune system is constantly adapting to new challenges.