This article critically analyses one of the last interference proceedings before the United States Patent and Trademark Office (USPTO) since the America Invents Act (AIA) was passed. It examines the interference proceeding between University of California, Berkeley and the Broad Institute for the patent on the use of the Clustered regularly interspaced short palindromic repeats (CRISPR) gene editing system, which was terminated by the Patent Trial and Appeal Board (PTAB) in February 2017. The aim is to review the ‘obviousness standard’ in US patent law and question whether, once the basics of a technique are well known, the application of the technology in different contexts becomes obvious too? How should inventorship be decided in such cases?