@stevegis_ssg There are real-life genetic disorders, mitochondrial wasting diseases, that amount to the mtDNA being sufficiently broken that mitochondria can't be replenished after birth. They take a couple of years to kill.
Awful diseases, but they're also exciting in the sense that some of these disorders can be permanently cured with a single-dose genomic medicine. We can't replace the broken mitochondria themselves yet, but their brokenness is often in them not being able to make a small number of very specific proteins; if genes for making these proteins were transplanted into nuclear DNA of a suitably chosen tissue, then, depending on the specific conditions, the availability of such a protein might be able to bypass the mitochondrial brokenness, and allow mitochondria to reproduce properly again.
These wonderful and life-saving medicines are usually priced in millions of dollars per dose, though, because capitalism. And in some cases, the dose must be administered very soon after birth, lest the slow mitochondrial depletion cause, say, irrepairable brain damage.
futurebird