TMF contains state-of-the-art microinjection and Embryonic Stem (ES) cell culture facilities and a fully functional barrier containment facility where the mice are housed. Animals are maintained on strict light controlled schedules and are periodically screened for health status. The facility provides any investigator access to the latest technology for generating transgenic and “knock-out” animals at very reasonable cost, on a non-for-profit basis. Transgenic mice carrying new or novel genes are created by microinjection of DNA into the pronuclei of fertilized eggs. Knock-out mice lacking specific genes of interest are created by homologous recombination in embryonic stem cells followed by injection into blastocysts to create chimeric mice.