The Bacterial Ancestry of Plastids and Mitochondria

Abstract

The mitochondria and plastids of eukaryotic cells contain distinctive DNAs that encode the ribosomal RNA and transfer RNA components of translation systems that are specific for these organelles. Comparative studies of these particular organelle genes and the RNAs they encode now provide the most compelling evidence available that mitochondrial and plastid genomes are descended from the genomes of bacteria-like organisms (“protomitochondria,” “protoplastids”) that entered into an endosymbiotic relationship with a primitive host cell bearing the nuclear genome.