Extreme sequence heteroplasmy in bat mitochondrial DNA.

Mitochondrial heteroplasmy is shown to be extensive when amplification products from the mitochondrial control region are cloned and sequenced from a European bat species. In contrast, a mitochondrial ribosomal RNA gene does not exhibit substantial levels of heteroplasmy when analyzed in an identical way. In the bat, heteroplasmy with respect to length as well as sequence seems to be transmitted from mother to offspring. Thus, the intra-individual sequence diversity seems to accumulate within the female germ line and its extent to be controlled primarily by purifying selection. Similar experiments in humans and a marsupial suggest that heteroplasmy may not be as uncommon among mammals as hitherto thought.