The aim of this trade document is the generation and supply of 6 different strains of genetically modified mice (4 transgenic mice with a mutated form of the human POLG, and 2 transgenic mice carrying the normal version of the human POLG). These animal models are needed to test potential therapies for the disease caused by mutations in POLG, and so the generation of these mice is included as a task in a project granted by the Fundació la Marató de TV3. The generation of these animal models must be done using the PiggyBac-on-Bac technology because this method ensures the generation of single-copy transgenic mice.