eukaryotes

New studies revise ideas about the symbiosis that gave mitochondria to cells and about whether the last common ancestor of all eukaryotes was one cell or many.

Mitochondria are most famous as sources of metabolic energy. But by splitting and combining, they can also release chemical signals to regulate cell activities, including the generation of neurons.

Neither animal, plant, fungus nor familiar protozoan, a strange microbe that sits in its own “supra-kingdom” of life foretells incredible biodiversity yet to be discovered by new sequencing technologies.

Symbiotic bacteria that dwell within insect cells are intricately intertwined with their hosts, prompting scientists to question when these bacteria stop being bona fide organisms and become part of the cell.