A new survey of the simple cells called Asgard archaea — a huge group of microbes discovered only a few years ago — is providing the clearest glimpse yet of the ancient symbiosis that helped create complex cells as we know them. Meanwhile, other researchers are arguing that genealogical attempts to trace all known eukaryotes back to a single common ancestral cell may be futile if that “ancestor” was really a population of diverse, gene-swapping cells. https://www.quantamagazine.org/rethinking-the-ancestry-of-the-eukaryotes-20190409/