Figure 2.

Hypothesis for the origin of MRP. This figure is based on [7], but modified to reflect present hypothesis of mitochondrial and eukaryotic evolution. The large black dots represent the point of duplication of the P-MRP ancestor. A: MRP was present in the last common ancestor of modern eukaryotes (the Eukaryotic Ancestor). Alternatively both MRP and P could have been present in the Last Universal Common Ancestor. B: MRP arose from a duplication of P after the Eukaryotic Ancestor, but before the ancestor of animals, fungi and plants. C: MRP arose from an early mitochondrial P within the Eukaryotic Ancestor.