Evolution of the nuclear envelope (NE) to form a container for most eukaryotic cellular DNA

Abstract

Eukaryogenesis, the emergence of eukaryotic cells, represents a pivotal evolutionary event. With a fundamentally more complex cellular plan compared to prokaryotes, eukaryotes are major contributors to most aspects of life on earth. For decades, we have understood that eukaryotic origins lie within both the Archaea and the α-proteobacteria. However, it is much less clear when, and from which precise ancestors, eukaryotes originated, or the order of emergence of distinctive eukaryotic cellular features. Many competing models for eukaryogenesis have been proposed, but until recently, the absence of discriminatory data made consensus elusive. Recent advances in paleogeology, phylogenetics, cell biology and microbial diversity, particularly the discovery of the Candidatus lokiarcheaota phylum, are now providing new insights into these aspects of eukaryogenesis. The new data include finessing the time frame during which the events of eukaryogenesis occurred, a more precise identification of the contributing lineages and their likely biological features. Signifi cant advances now pinpoint the prokaryotic origins of key eukaryotic cellular processes, such as intracellular compartmentalisation, with major implications for models of eukaryogenesis.