With the development of transmitochondrial technique,we have successfully establisheda a transmitochondrial mouse model carrying mutated mitochondrial DNA.Now there are three methods to produce transmitochondrial mice.One is direct mitochondrial microinjection.The second is by fusing cytoplasts produced by enucleation of cells(donor) derived from patients or controls with undifferentiated female mouse embryonic stem cells and then injecting the embryonic stem cells into blastocysts.The third is direct by fusing cytoplasts with one-cell mouse embryo.With the discovery of a number of mitochondrial related diseases,tramsmitochondrial mice containing human mitochondrial disorders will have a great value to investigate mtDNA mutation and mitochondrial defect pathogenesis,evaluate gene therapy of diseases caused by these mutations and screen drugs of treating mitochondrial diseases.