The NIDCR DIR Scientific Cores provided research support for intramural investigators performing studies on dental and craniofacial diseases. The Gene Targeting Core (GTC) allows investigators to "add" or "subtract" genes in mice to develop animal models of relevant human diseases for research and to discover the affect of specific genes on host physiology. The GTC generated chimeric mice resulting in germline transmission of the genes of interest. In addition new gene knockout and transgenic mice were created and/or re-established. The murine embryonic stem cell service successfully completed gene targeting experiments. The GTC also provided an important scientific support service by cryopreserving embryos and sperm from murine animal models. These services contributed to over 100 research and review publications (reported in ZIA projects). Testing is underway for additional services, including IVF services for murine models and development of additional murine embryonic stem cell lines. The Combined Technical Research Core was formed to put several core functions under one Core Chief and a Core Director, including DNA Sequencing, which provided over a thousand reactions for NIDCR DIR investigator-led research, Flow Cytometry and Cell Sorting, Cell Elutriation, Laser Capture Microscopy, and Histology.