University of Pennsylvania researchers have developed a powerful new technique for editing the genetic code, using “zinc fingers” to disrupt a gene in patients’ T cells (the type attacked by the AIDS virus) and have then infused those cells back into the body.

A clinical trial is now under way to see if the treated cells will reconstitute a patient’s immune system and defeat the virus.

If so, it would provide a general method for generating new crop plants, treating many human diseases, and even making inheritable changes in human sperm or eggs.