This work was supported in part by the "Reproductive health and major birth defects prevention and control research" Key Special Fund (No. 2016YFC1000601), the National Natural Science Foundation of China (Grant Nos. 31371521, 81370766, 81401254, 81570101, 81671121, 31601187, 81521002), the Guangdong Province Science and Technology Project (2014TQ01R683, 2017A020 214005, 2016A020216023, 2015A030310119, 2016B030229008), the Bureau of Science and Technology of Guangzhou Municipality (201505011111498), the "Reproductive health and major birth defects prevention and control research" Key Special Fund (Nos. 2016YFC1000201 and 2016YFC1000302), the Ministry of Science and Technology of China Grants (973 program; 2014CB943203), and the Beijing Nova Program (xxjh2015011).
Mitochondrial diseases are maternally inherited hetero- geneous disorders that are primarily caused by mitochondrial DNA (mtDNA) mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy,...