Exploring microbial dark matter to resolve the deep archaeal ancestry of eukaryotes

The origin of eukaryotes represents an enigmatic puzzle, which is still lacking a number of essential pieces. Whereas it is currently accepted that the process of eukaryogenesis involved an interplay between a host cell and an alphaproteobacterial endosymbiont, we currently lack detailed information regarding the identity and nature of these players. A number of studies have provided increasing support for the emergence of the eukaryotic host cell from within the archaeal domain of life, displaying a specific affiliation with the archaeal TACK superphylum. Recent studies have shown that genomic exploration of yet-uncultivated archaea, the so-called archaeal ‘dark matter’, is able to provide unprecedented insights into the process of eukaryogenesis. Here, we provide an overview of state-of-the-art cultivation-independent approaches, and demonstrate how these methods were used to obtain draft genome sequences of several novel members of the TACK superphylum, including Lokiarchaeum, two re...

真核生物的起源堪称一道难解的谜题，至今仍缺失诸多关键拼图碎片。目前学界普遍认为，真核生物发生（eukaryogenesis）过程涉及宿主细胞与α-变形菌门内共生体（alphaproteobacterial endosymbiont）之间的相互作用，但我们目前仍缺乏关于这两类参与者的具体身份与本质的详细信息。多项研究不断提供支持证据，表明真核宿主细胞起源于古菌域（archaeal domain of life）内，并与古菌TACK超门（TACK superphylum）存在特定的亲缘关系。近期研究表明，对尚未培养的古菌——即所谓的古菌"暗物质"——进行基因组探索，能够为真核生物发生过程提供前所未有的见解。本文综述了当前最先进的非培养依赖研究方法，并展示了如何利用这些方法获取TACK超门多个新类群的草图基因组序列，包括洛基古菌（Lokiarchaeum）、两……