1999/03/05 by Michael W. Gray, Gertraud Burger, B. Franz Lang · 7 citations
Biochemistry, Genetics and Molecular Biology · Environmental Science · #Protist diversity and phylogeny #Genomics and Phylogenetic Studies #Microbial Community Ecology and Physiology
paper · doi:10.1126/science.283.5407.1476
openalex publication_date 1999/03/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
The serial endosymbiosis theory is a favored model for explaining the origin of mitochondria, a defining event in the evolution of eukaryotic cells. As usually described, this theory posits that mitochondria are the direct descendants of a bacterial endosymbiont that became established at an early stage in a nucleus-containing (but amitochondriate) host cell. Gene sequence data strongly support a monophyletic origin of the mitochondrion from a eubacterial ancestor shared with a subgroup of the alpha-Proteobacteria. However, recent studies of unicellular eukaryotes (protists), some of them little known, have provided insights that challenge the traditional serial endosymbiosis-based view of how the eukaryotic cell and its mitochondrion came to be. These data indicate that the mitochondrion arose in a common ancestor of all extant eukaryotes and raise the possibility that this organelle originated at essentially the same time as the nuclear component of the eukaryotic cell rather than in a separate, subsequent event.