Each of the three domains of life exhibits a unique motility structure: while Bacteria use flagella, Eukarya employ cilia, and Archaea swim using archaella. Since the new name for the archaeal motility structure was proposed, in 2012, a significant amount of new data on the regulation of transcription of archaella operons, the structure and function of archaellum subunits, their interactions, and cryo-EM data on in situ archaellum complexes in whole cells have been obtained. These data support the notion that the archaellum is evolutionary and structurally unrelated to the flagellum, but instead is related to archaeal and bacterial type IV pili and emphasize that it is a motility structure unique to the Archaea.

生命的三个领域中的每一个都表现出独特的运动结构：细菌使用鞭毛，真核生物使用纤毛，古细菌使用古细菌游泳。自从 2012 年提出古菌运动结构的新名称以来，大量关于古菌操纵子转录调控的新数据、古菌亚基的结构和功能、它们的相互作用以及原位古菌的冷冻电镜数据已获得全细胞复合物。这些数据支持古细菌是进化的，在结构上与鞭毛无关，而是与古细菌和细菌 IV 型菌毛相关的观点，并强调它是古细菌独有的运动结构。