It has already been mentioned that the genetic code of mitochondria differs from the general one. The mtDNA of the C - plasma differs from that of the N plants in numerous restructurings. In this way have hybrid genes, i.e. genes that consist partially of an ATPase gene and partially of a cytochrome - oxidase gene been developed. The mtDNA of the T variety displays an even higher degree of restructuring. In the mitochondria of the S variety were two linear plasmids found.
Plasmids are additional small DNA molecules typical for bacteria.
During the last years did they become indispensable tools of genetic engineering. It seems as if the hybrid proteins produced in the CMS varieties would be deposited in the inner mitochondrial membrane and would impair its function. This guarantees that one type is transported into one organelle, another into a second organelle while a third type may remain in the cytosol. Enzymes of the same activity and specificity but of different structures and reaction kinetics are called isoenzymes . Mitochondria develop by division, too.