http://www.the-scientist.com/blog/display/57199/

Mitochondrial genomes are not uniform across cells of the body as previously believed, but vary between different tissue types, according to a study published online today (March 3) in Nature.

"I was surprised," said molecular cell biologist Hans Spelbrink of the University of Tampere, Finland, who was not involved in the research. "Mostly the assumption is that from the start of life individuals are homoplasmic," meaning that within an individual, mitochondrial DNA (mtDNA) is the same. However, the results of this study demonstrate "that each individual is a mosaic of multiple [mt]DNA types in various frequencies in different tissues," he said.

The Scientist: Surprising mtDNA diversity - The Scientist - Magazine of the Life Sciences http://www.the-scientist.com/blog/display/57199/#ixzz0h8zcc4wC