With our knowledge and established experimental repertoire we are dedicated to support experiments involving gene-modified mice at the University of Zurich and in the greater Zurich area. By pronuclear injection we generate conventional transgenic mouse strains. Our embryonic stem cell and the complementary blastocyst injection service enable the establishment of new mouse strains with specific targeted mutations. While the ES cell approach is still standard, it is currently being replaced by the new CRISPR/Cas9 technology. By injection of Cas9 enzyme and a guide RNA for a specific genomic location into pronuclei, rapid introduction of deletions and insertions is possible, leading frequently to abrogation of gene function. When an oligonucleotide, i.e. including point mutations, is co-injected, these can be specifically brought into the genome. Also targeting vectors, carrying larger transgenes such as GFP or Cre are integrated by homologous recombination, when coinjected into the pronucleus. Beyond these transgenic approaches we are offering strain cryo-preservation and recovery. By providing an embryo transfer service for pathogen removal we are actively involved in management of the health of the local mouse colonies.