For phenomenology, the central feature of experience is a structure called intentionality, which correlates all things experienced with the mode of experience to which the experience is referenced. 2001, Lois Bloom, Erin Tinker, Ellin Kofsky Scholnick, The Intentionality Model and Language Acquisition, page 10,
PAM(Protospacer adjacent motif) sequence in a CRISPR is a 2-6 base pair DNA sequence immediately following the DNA sequence targeted by the Cas9 nuclease in the CRISPR bacterial adaptive immune system. PAM is a component of the invading virus or plasmid, but is not a component of the bacterial CRISPR locus. Cas9 will not successfully bind to or cleave the target DNA sequence if it is not followed by the PAM sequence.
Think of it like a search-and-rescue mission for DNA. Crispr uses guide RNA as a homing device; it's designed in a lab to match up with a section of DNA designated for editing. In therapeutic uses, this could be a genetic abnormality that causes disease. That guide molecule is joined with an enzyme known as Cas9 (CRISPR's fuller name is actually CRISPR-Cas9). The enzyme acts like scissors, making a cut in the DNA where the RNA guided. By adding DNA with the correct sequence, scientists hope to be able to correct the underlying genetic defects that cause disease.