On the Archaeal Origins of Eukaryotes and the Challenges of Inferring Phenotype from Genotype.
If eukaryotes arose through a merger between archaea and bacteria, what did the first true eukaryotic cell look like? A major step toward an answer came with the discovery of Lokiarchaeum, an archaeon whose genome encodes small GTPases related to those used by eukaryotes to regulate membrane traffic. Although 'Loki' cells have yet to be seen, their existence has prompted the suggestion that the archaeal ancestor of eukaryotes engulfed the future mitochondrion by phagocytosis. We propose instead that the archaeal ancestor was a relatively simple cell, and that eukaryotic cellular organization arose as the result of a gradual transfer of bacterial genes and membranes driven by an ever-closer symbiotic partnership between a bacterium and an archaeon.
MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK. Electronic address: g.dey@ucl.ac.uk.
Gautam
G
Dey
National Centre for Biological Sciences, TIFR, GKVK, Bellary Road, Bengaluru 560065, India.
Mukund
M
Thattai
MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK. Electronic address: b.baum@ucl.ac.uk.
Buzz
B
Baum
D001105:Archaea / Q000235:genetics*; D001419:Bacteria / Q000235:genetics*; D056890:Eukaryota / Q000235:genetics*; D019143:Evolution, Molecular; D016678:Genome; D005838:Genotype; D010641:Phenotype; D010802:Phylogeny
GTPase; Lokiarchaeum; eukaryogenesis; evolution