4 ideas
In June 2012 Jennifer Doudna and Emmanuelle Charpentier published in Science that the Cas9 enzyme, guided by a programmable RNA, could cut DNA at a chosen site in a test tube. The Broad then filed for fast-tracked patents covering eukaryotic cells, and the U.S. patent office later ruled that the human-cell application was not 'obvious' from the Berkeley work, leaving the two sides with split rights and a long, costly dispute.
CRISPR began as microbiologists studying odd repeated DNA sequences that bacteria use to fight viruses, with no application in mind. The tool that reshaped medicine came from funding and pursuing a question about how a natural system works, not from targeting a practical goal. Its payoff could not have been predicted or commissioned in advance.
Doudna's method was to work out the three-dimensional structure of a molecule in order to explain what it does, first with ribozymes and then with Cas9. Knowing the molecular shape is what turned a bacterial immune system into an engineerable tool.
The ethics of gene editing rest on two distinctions: somatic edits, which affect only the patient, versus germline edits, which are inherited; and treating disease versus enhancing traits. He Jiankui's 2018 birth of CRISPR-edited twins showed these lines are enforced by norms, not technical limits. That shifted the question from whether heritable editing can be done to who decides where therapy ends and enhancement begins, and whether access will be fair.