In this video presentation in the Google Techtalk series, biomedical gerontologist Aubrey de Grey discusses the role of mitochondrial DNA (mtDNA) in aging: "Among other things, mitochondria perform the chemistry of breathing - they extract energy from nutrients by exquisitely regulated chemical reactions that consume oxygen and create [carbon dioxide]. This vital function depends on the 13 proteins encoded by the mitochondrial DNA (mtDNA), as well as on hundreds of proteins that are encoded in our more famous genome and imported across the mitochondrial surface after construction in the body of the cell. The mtDNA accumulates mutant, non-functional variants far faster than our main genome, so 20 years ago scientists began looking at the idea of putting copies of the 13 genes of interest into the nucleus after making modifications that would cause them to be processed by the same 'protein import' machinery that processes the mitochondrion's many other proteins, thus making the mtDNA itself superfluous and mutations in it harmless. ... Progress has been very erratic in the meantime but is now very rapid, partly because of Methuselah Foundation-funded research. However, this approach may still prove impossible, so many other, ostensibly simpler ideas - some more promising than others - have been proposed, and I will describe some of these too."