Rather than introducing small chunks of DNA as other viruses do, some giant viruses can contribute more than 1 million base pairs to a host’s genome, broadening the ways in which viruses may shape eukaryote evolution.

Far from being inert fat-storage depots within cells, these lipid-loaded organelles recruit immune proteins and block bacterial growth.

The 12-year-long endeavor reveals Prometheoarchaeum as a tentacled cell, living in a symbiotic relationship with methane-producing microbes.

The ancient organisms appear to be more closely related to eukaryotes than previously appreciated.

Identification of new archaea species elucidates the domain’s unique  biology and sheds light on its relationship to eukaryotes.

The 10-micrometer-long flagellate cell might have a big story to tell about the evolution of eukaryotes.

Did endosymbiosis—and the innovations in membrane bioenergetics it engendered—make it possible for eukaryotic life to evolve?

Deep-sea microbes possess hallmarks of eukaryotic cells, hinting at a common ancestor for archaea and eukaryotes.

A red alga appears to have adapted to extremely hot, acidic environments by collecting genes from bacteria and archaea.