genome editing

Genome editing is like using a word processor on the text of life. Instead of leaving the DNA sequence as it was inherited, scientists go to a chosen spot, delete a letter, swap one for another, or paste in a new passage — all at a precise address chosen in advance.

Technically, genome editing means making deliberate, targeted changes to the DNA sequence of a living cell or organism at a known location. Most modern methods work by directing a molecular tool to a matching DNA sequence, where it cuts or chemically alters the DNA; the cell's own repair machinery then completes the edit, either by joining the ends back together or by copying from a supplied template.

Editing differs from older genetic engineering, which often inserted genes at random positions. Targeting a specific site makes the outcome more predictable and controllable. Still, no method is perfect: edits can land at unintended off-target sites, repair can produce unexpected sequences, and edits in the germ line are passed to future generations, which raises distinct safety and ethical questions.