3. What natural process inspired the discovery of CRISPR?

The discovery of CRISPR was inspired by the observation of a peculiar pattern in bacterial DNA. Scientists noticed repeated sequences of DNA, called "clustered regularly interspaced short palindromic repeats" (CRISPR), interspersed with unique "spacer" sequences. Further investigation revealed that these spacer sequences matched the DNA of viruses that infect bacteria (bacteriophages).<br /><br />Essentially, bacteria were found to be integrating snippets of viral DNA into their own genomes. This process is a natural bacterial defense mechanism against viral infection. When a bacteriophage attacks, the bacteria can transcribe these CRISPR sequences into RNA molecules. These RNA molecules, along with a protein called Cas (CRISPR-associated), then act like a guided missile system. The RNA guides the Cas protein to the matching viral DNA, where Cas cuts the viral DNA, disabling the virus and preventing infection.<br /><br />This natural adaptive immune system in bacteria inspired scientists to adapt CRISPR-Cas as a gene-editing tool. By designing specific guide RNAs, researchers can direct the Cas protein to cut DNA at precise locations in any organism, enabling targeted gene modification.<br />