Although the CRISPR/Cas9 system has seen widespread application in editing the nuclear genome, using it to edit the mitochondrial genome has been problematic. The main hurdles have been a lack of suitable editing sites in the small mtDNA, and the traditional difficulty of importing the guide RNA into the mitochondrial matrix where nucleoids can be accessed.
source https://phys.org/news/2021-02-crispr-mitochondria-biotech.html
