A fix for mitochondrial DNA

Mitochondrial DNA (mtDNA) is passed from mother to offspring, with sperm mitochondria contributing no DNA to the embryo. Mutations in mtDNA are linked to a range of diseases including type 2 diabetes, mitochondrial myopathies and neuropathies. This paper demonstrates in a non-human primate model that a defective mitochondrial genome can be replaced by transferring the spindle–chromosome complex from one egg into an egg from which the nucleus is removed. The experiment utilized unfertilized eggs from two female rhesus macaque monkeys as ‘nuclear’ and ‘cytoplasmic’ donors. The resulting eggs were fertilized and developed into embryos that were implanted in surrogates resulting in the birth of healthy twins, named Mito and Tracker in a reference to the probes used for imaging mitochondria. This suggests a route to an assisted reproductive technology approach to preventing mtDNA disease transmission in affected families. See also the Nature Editorial on the ethical aspects of this work in the 27 August issue (Vol. 460, p. 1057).