From 1980 onward, Mario Capecchi begins research at the University of Utah, initially without federal funding since the project was considered too risky, aimed at demonstrating that DNA artificially introduced into a mammalian cell can recombine homologously — that is, be specifically exchanged — with the corresponding sequence already present on the chromosome. Capecchi's central technical achievement consists of developing a method for injecting the modified DNA directly into the cell nucleus, drastically increasing the efficiency of the recombination process compared to earlier methods, and demonstrating with this system that defective genes can be repaired or altered with targeted precision, opening the conceptual door to selective editing of any gene in the genome. Capecchi presents his results at a biology conference in 1984, in parallel and independently of Oliver Smithies's work, who was pursuing the same goal via a different experimental strategy initially focused on correcting globin mutations. The practical culmination of both approaches came when combined with the mouse embryonic stem cells cultured by Martin Evans, which allowed targeted gene editing to be transferred from cultured cells to complete living mice whose offspring inherited the modification, giving rise to "knockout mouse" technology. Capecchi and Smithies shared the Wolf Prize in Medicine in 2002; the 2007 Nobel recognized both together with Evans.