The short RNA sequence that tells a CRISPR enzyme where in the genome to cut.
About twenty bases, complementary to the target site. It is the reason CRISPR is programmable: changing the target means synthesising a different guide, not engineering a different protein. Off-target cutting happens when a guide is similar enough to somewhere else in the genome.
Articles that define guide rna in context.
How CRISPR finds one address in three billion letters, why the scissors were never the innovation, and why a precise edit is a screening campaign rather than an operation.
Biotechnology explained through the four things you can now do to a genome, the order the field acquired them, and what each one unlocked.
