Samllest living micro-organism
Scientists believe that the micro-organism may provide them an insight into what the first life on Earth looked like. Photo Credit: UiO/MERG

Scientists have discovered one of the world's smallest and oldest known micro-organism living in the sludge of a lake in Ås, 30 km south of Oslo in Norway.

Researchers from the University of Oslo, Norway, examined the micro-organism, an algae-eater, called hereafter as the protozoan and compared its genes with other known species in the world. They found that the micro-organism did not belong to any other species including a fungus, alga, parasite, plant or animal.

 "We have found an unknown branch of the tree of life that lives in this lake. It is unique," Kamran Shalchian-Tabrizi, head of the Microbial Evolution Research Group (MERG) at the University of Oslo told the research magazine Apollon.

 "So far we know of no other group of organisms that descend from closer to the roots of the tree of life than this species. It can be used as a telescope into the primordial micro-cosmos," he added.

The protozoan has been identified as a new species called Collodictyon (single celled eukaryote organism). It is said to be one billion years old and a remotest relative to humans.  These protozoans are 30 to 50 micrometres long and live down in the sludge at the bottom of the lake.

"The micro-organism is among the oldest, currently living eukaryote organisms we know of. It evolved around one billion years ago, plus or minus a few hundred million years. It gives us a better understanding of what early life on Earth looked like," Kamran said.

Eukaryote organisms are made up of cells that have membrane-bound nucleus which holds the genetic material. These organisms may be multicellular (multi-celled) or unicellular (single-celled) organisms. All animals and other organisms including plants, fungi and protists are eukaryotes.

Moreover, the protozoan is said to have four flagella, which is important for cells to move. Even human cells have one flagellum. Scientists say that this new species' family should belong to somewhere between the oldest group of single-celled parasites which has two flagella and oldest group of some amoebae, which has only one flagellum.

Researchers believe that the discovery may give them an insight into what life looked like on earth almost one thousand million years ago.