>>10024099Fast forward to 2020 these guys are on it:
Bacterial flagellar motor PL-ring disassembly subcomplexes are widespread and ancient
https://www.pnas.org/content/early/2020/04/01/1916935117?utm_source=TrendMD&utm_medium=cpc&utm_campaign=Proc_Natl_Acad_Sci_U_S_A_TrendMD_0Tldr: they determine one of those ancient genes is a ring protein that helps fold the cell membrane and formed the scaffold for other proteins to attach.