Tina Hesman Saey in Science News:
One parasite that feeds on algae is so voracious that it even stole its own mitochondria’s DNA.
Mitochondria — the energy-generating parts of cells — of the parasitic plankton Amoebophyra ceratii seem to have transferred all of their DNA to the cell’s nucleus, researchers report April 24 in Science Advances. The discovery is the first time that scientists have found an oxygen-using organism with fully functional mitochondria that don’t have any mitochondrial DNA. (Some anaerobic organisms, which don’t need oxygen, and thus mitochondria, to survive, have also lost mitochondrial DNA.)
Mitochondria are thought to be bacteria that were captured by other cells and eventually became standard parts of eukaryotic cells — cells that encase their DNA and other parts in membranes. Mitochondria reside outside of the nucleus in a cell’s jellylike guts, the cytoplasm. Part of the settling-in process involved relocating some genes needed for mitochondria’s function to the nucleus of host cells. But most mitochondria kept at least a few genes. (Human mitochondria held on to 37 genes.)
Not so for A. ceratii, Uwe John of the Alfred Wegener Institute in Bremerhaven, Germany, and colleagues discovered.