Newly Discovered Organisms Belong To Brand-New Branch On The Tree Of Life


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockNov 16 2018, 17:51 UTC

One of the new microbes discovered by Dal researchers. Yana Eglit

A researcher on a hike near Halifax has found two species from a rarely observed group of microbes, one of which was completely new to science. Once the species were analyzed in the lab at Dalhousie University, scientists realized that the whole group belongs to a new branch on the tree of life. The discovery is reported in this week’s Nature.  

The two species are hemimastigotes, a relatively peculiar group of microorganisms. They are eukaryotic protists. Just like animals, plants, and fungi, these organisms have their genetic material in a nucleus (that’s the eukaryote part), but they are nothing like animals, plants, or fungi. They are unicellular organisms and have two lines of flagella, hair-like protuberances that they use to move and capture other microbes to feed on.  


“It’s an unusual looking group of organisms,” first author Yana Eglit, a graduate researcher who collected the samples, said in a statement. “The way they behave under the microscope, you won’t immediately spot them.”

The two species are Spironema, which has been observed with microscopes only a few times since its discovery in the 19th century, and Hemimastix kukwesjijk, which is named after a ravenous, hairy ogre from the Mi’kmaq folklore – the First Nation people in whose territory the microbe was discovered.

The team collaborated with several other researchers to quickly analyze the microbes' genetic material. A new technique was employed to extract a significant amount of genetic information from single cells. The genetic information collected wasn’t a complete genome, but it was enough to show something incredible. It allowed the scientists to compare the two species to other species and learn they didn’t belong to any known “kingdom”, one of the subdivisions of life. They are on their own.


“This discovery literally redraws our branch of the ‘Tree of Life’ at one of its deepest points,” explained lead researcher Professor Alastair Simpson. “It opens a new door to understanding the evolution of complex cells – and their ancient origins – back well before animals and plants emerged on Earth.”

The team didn’t just amend the tree of life. Eglit was able to grow and maintain populations of hemimastigots, the first person to do so. Being able to culture these microorganisms will allow researchers to unlock their full genome.