Abstract

The origin of eukaryotes is one of the major transitions in life’s history, yet the timeline of how the eukaryotic cell was assembled remains surprisingly unclear. Both fossils and molecular clocks give broad ranges, making it difficult to tell whether eukaryogenesis was a sudden event or a long, staged process. In this talk, I will present a different line of evidence based on the order of gene duplications across key cellular systems. By linking duplicated genes to specific intracellular features, we can reconstruct the sequence in which cytoskeletal components, membrane-trafficking systems, and metabolic innovations emerged. Time-resolving these duplications also allows us to frame eukaryogenesis within the palaeo-environmental conditions of early Earth. The resulting picture supports a protracted, stepwise assembly of eukaryotes — beginning before the widespread rise of oxygen.