The first tentatives to make mammalian transgenic animals; the main reasons and the knowledge of early embryonic phasesThe main techniques used to introduce the exogenous DNA transcripts. identification of integration and functional expressionOrgan and cellular targeting.The principal methodologies used for the production of transgenic animals: pronuclear microinjection, chimeric animals, sperm mediated transfer, nuclear transplantation, intracytoplasmic transfer, germ cell transplantation,The principal techniques used for gene editing: problems and applicationsCosts and risks of the production of transgenic animals