Extranuclear inheritance

Extranuclear genes are those located in the chloroplasts and mitochondria. They were discovered in plants by Karl Correns in 1909. They have been linked to several rare and deadly diseases in humans. Defects in the mitochondrial DNA reduce the amount of ATP that a cell can produce. The organs most affected by these mutations are that ones that need the most energy such as the muscles and the nervous system. These diseases are always inherited from the mother because the mitochondria passed to the zygote all come from the cytoplasm of the egg.