Perturbations in mitochondrial dynamics precede cellular dysfunction and have been implicated in the progression of age-related diseases such as sarcopenia.40 To gain insight into the effects of aging on mitochondrial dynamics in skeletal muscle among species, we assessed key proteins involved in fusion ((mitofusins1 and 2 (Mfn1 and Mfn2)) and fission (fission 1 protein (Fis1) and dynamin-related protein (Drp1)). The gene discussed is FIS1; the disease is sarcopenia.