Another example would be the discovery that the ECM (extracellular matrix) plays a huge role in cellular development. Completely unrecognized until experiments done by Mina Bissel's lab opened up an entirely new field in cellular biology.

Superresolution microscopy. It blew through a long-standing limitation- the best resolution was determined by the wavelength of light passing through a lens. That and other recent discoveries in microscopy like light-sheet microscopy have turned microscopy on its head.

I don't understand. Are you implying this paper is a "major finding"?

Many things that happen in biology occur without any real meaning or utility.

No, I'm agreeing with you. I think it rare that any mature field these days is "turned on its head". I doubt most of the examples given by other comments would qualify if you dig into them.

A good example would be induced pluripotent stem cells nobody thought that that can happen but once it was obvious that you just needed a few transcription factors to move cells from state-to-state. Completely trans formed a field that was already mature