I am looking to extract mtDNA to run on a simple agarose gel. Protocols online are contradictory and seem to jump between talking about cells to talking about tissue and back.
For pure mtDNA you will need to undertake CsCl centrifugation. You can get a good extraction of mitochondria which can then be lysed using a sucrose centrifugation. Tjis worked well for me many years ago https://www.researchgate.net/publication/13941623_Mitochondrial_DNA_variation_in_the_scallop_Pecten_maximus_L_assessed_by_a_PCR-RFLP_method