Bacteria write DNA to fight viruses — and it looks like a cousin of what guards our own chromosomes

Columbia University scientists have found a bacterial defence system, published in Nature, that works nothing like CRISPR. Instead of cutting DNA, the system, called DRT10, uses an enzyme to write brand-new DNA inside the cell from an RNA template — a trick for stopping viruses that echoes telomerase, the enzyme that protects the ends of human chromosomes. Senior author Samuel Sternberg says that difference is exactly the point: a fresh starting point for future tools to engineer cells, and a clue to an ancient step in evolution.