For such crucial biological actors, much remains unknown about exactly how mitochondria function. A new study, published Aug. 12 in the online journal PLoS One, sheds light on mitochondrial biology. Using genetic engineering, researchers interrupted the activity of individual genes directly involved in the production of energy within mitochondria. "If we knock down the function of specific system components, what happens?" said study leader Marni J. Falk, M.D., who directs the Mitochondrial-Genetics Disease Clinic at The Children's Hospital of Philadelphia. "Our ultimate goal is to translate the knowledge into targeted therapies, that is, effective ways to intervene. But first we need to understand the underlying disease mechanisms."