Eukaryogenesis

Common card · No. 428690

Eukaryogenesis, the process which created the eukaryotic cell and lineage, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The process is widely agreed to have involved symbiogenesis, in which an archaean and one or more bacteria contributed to the lineage leading to the last eukaryotic common ancestor (LECA). It appears also to have involved horizontal gene transfers from other groups of bacteria, with some of these transfers mediated by giant viruses. The LECA had a new level of complexity and capability, with a nucleus, facultatively aerobic mitochondria, sex (meiosis and syngamy), flagella, a dormant cyst with a cell wall of chitin and/or cellulose and peroxisomes. The sequence of steps involved in eukaryogenesis has been disputed; mitochondria, an endomembrane system, and the nucleus arose in an unknown sequence. Another possibility is viral eukaryogenesis, in which a viral infection of an archaean enabled...

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