Blastocyst Injection to Generate Chimeric Mice Search Clinical Trials Find a Researcher Order a Test Blastocyst injections will be performed to generate chimeras from one to two mouse ES targeted clones. This procedure comprises three days of mouse ES cell injection into blastocysts and transfer of injected embryos into pseudopregnant foster mice. Payment of this fee does not guarantee the generation of targeted mice because of the variability in germline transmission of different mouse ES cell lines and chimeras. We inject both in house targeted ES cells as well as ES cells that have been imported from consortiums or collaborators. Please inquire for details. General Overview of the Process Core expands ES cells for microinjection. (If the ES cells have been imported from another institution, we require mycoplasma testing and chromosome counting prior to microinjection.) Core prepares blastocyst-stage embryos, injects targeted ES cells into embryos, and transfers them into pseudopregnant females. Core informs investigator of extent of chimerism observed in pups. Core arranges for transfer of chimeric mice to investigator. Investigator breeds chimeric mice for germline transmission. Investigator breeds heterozygotes together to generate homozygotes for desired genetic modification.