Although that for a long-time symbiosis was considered to be quite exceptional and restricted to few classical textbooks examples like lichens, American biologist Lynn Margulis (1938-2011) devoted most of her professional life to demonstrate that it is in fact a pervasive mechanism uniting what would otherwise would appear as isolated biological species and lineages. Starting with her seminal assay, “On the origin of mitosing cells,” published in the Journal of Theoretical Biology in 1967 (authored as Lynn Sagan), her lifelong work on eukaryogenesis and the role of symbiosis in evolution stands as a valid and authoritative contribution to science.