A New Branch of Life?

Researchers investigate a microorganism that may warrant a new eukaryotic kingdom in the classification of life.

May 1, 2012
Jef Akst


It’s not a plant. It’s not an animal or fungus. Collodictyon is an algae-eating protozoan found in the sludge of a Norwegian lake. And, sequencing bits of its genome, including its ribosomal DNA, Kamran Shalchian-Tabrizi of the Microbial Evolution Research Group (MERG) at the University of Oslo and colleagues discovered that it’s not like anything else on earth, falling on the tree of life somewhere between single-celled parasites called excavates and amoebas. The organism could thus represent a new kingdom of life, the authors suggested.

“The early and distinct origin of Collodictyon suggests that it constitutes a new lineage in the global eukaryote phylogeny,” the authors wrote in in the journal Molecular Biology Evolution.

Among its obscurities, Collodictyon has four flagella, as opposed to the one of mammals, fungi and amoebae, and the two of algae, plants, and excavates. Furthermore, it has the internal structure of a parasite, but hunts like an amoeba. The researchers suggest that the bizarre organism may represent ancient morphologies among eukaryotes, and thus provide clues of early life. “Overall, this shows that Collodictyon is a key lineage to understand early eukaryote evolution,” they wrote.

(Hat tip to GenomeWeb.)