Phagocytosis, or ‘cell eating’, is a eukaryote-specific process where particulate matter is engulfed via invaginations of the plasma membrane. The origin of phagocytosis has been central to discussions on eukaryogenesis for decades­, where it is argued as being either a prerequisite for, or consequence of, the acquisition of the ancestral mitochondrion. Recently, genomic and cytological evidence has increasingly supported the view that the pre-mitochondrial host cell—a bona fide archaeon branching within the ‘Asgard’ archaea—was incapable of phagocytosis and used alternative mechanisms to incorporate the alphaproteobacterial ancestor of mitochondria. Indeed, the diversity and variability of proteins associated with phagosomes across the eukaryotic tree suggest that phagocytosis, as seen in a variety of extant eukaryotes, may have evolved independently several times within the eukaryotic crown-group. Since phagocytosis is critical to the functioning of modern marine food webs (without it, there would be no microbial loop or animal life), multiple late origins of phagocytosis could help explain why many of the ecological and evolutionary innovations of the Neoproterozoic Era (e.g. the advent of eukaryotic biomineralization, the ‘Rise of Algae’ and the origin of animals) happened when they did.

吞噬作用或“细胞吞噬”是一种真核生物特异性过程，其中颗粒物质通过质膜的内陷被吞噬。几十年来，吞噬作用的起源一直是真核发生讨论的核心，它被认为是获得祖先线粒体的先决条件或结果。最近，基因组和细胞学证据越来越支持以下观点，即线粒体前宿主细胞是一种真正的在“Asgard”古细菌中分支的古细菌无法吞噬，并使用替代机制来合并线粒体的 alphaproteobacterial 祖先。事实上，与整个真核树中的吞噬体相关的蛋白质的多样性和可变性表明，如在各种现存的真核生物中所见，吞噬作用可能在真核生物冠群内独立进化了几次。由于吞噬作用对现代海洋食物网的功能至关重要（没有它，就不会有微生物环或动物生命），吞噬作用的多个晚期起源可以帮助解释为什么新元古代的许多生态和进化创新（例如真核生物矿化的出现、“藻类的兴起”和动物的起源）发生时。