Mitochondria and Their Ancestors

• November 1998: The most mitochondrion-like bacterium so far found is the bacterium that causes typhus in humans. Typhus was one of the worst diseases of humans, well into this century, and is thought to have been responsible for some of the great plagues of history. Rickettsia, as it is called, cannot survive on its own (it has lost the genes that would allow it to do so): it must live inside other cells. It has only one-quarter of the DNA of E. coli, for example, though it has ten times the DNA of the most bacteria-like mitochondrion.

  The most primitive-looking mitochondrion so far found lives inside a mud-dwelling protist called Reclinomonas americana.

• What is Reclinomonas?
• Images of Reclinomonas americana

  By 2005, there was evidence that a mysterious cell component called a hydrogenosome was some sort of relative of a mitochondrion. Eventually, this will help to clear up the origin of both of them. The Scientist, March 3, 2005 (Free registration required.). The paper was in Nature, which provides no free Web access.

Contents last updated September 30, 2005.
Links checked September 30, 2005