A team of Swedish bioboffins has, on Wednesday, presented its discovery of a new microbe which represents a missing link in the evolution of complex life. The research provides more information about the development of Eukaryotic cells, the complicated unit that allows larger biomasses (such as ameobas, plants and human bodies) to develop.
The study, published in Nature this week, features a research team based mainly in Uppsala University in Sweden presenting their discovery of a new microbe, which they claim represents a missing link in the evolution of complex life. The study provides a new understanding of how the complex cell types that comprise plants, fungi, animals and humans evolved two billion years ago.
According to the abstract of their study, titled "Complex archaea that bridge the gap between prokaryotes and eukaryotes", the origin of those complex cells, the eukaryotes, "remains one of the most contentious puzzles in modern biology."
The researchers from Uppsala University in Sweden, who collaborated with researchers from Bergen and Vienna, reported the discovery of a new group of Archaea, the Lokiarchaeota (or "Loki" for short), and identify it as a missing link in the evolutionary lineage of eukaryotes.
"The puzzle of the origin of the eukaryotic cell is extremely complicated, as many pieces are still missing. We hoped that Loki would reveal a few more pieces of the puzzle, but when we obtained the first results, we couldn’t believe our eyes. The data simply looked spectacular," said Thijs Ettema at the Department of Cell and Molecular Biology, Uppsala U.
"By studying its genome, we found that Loki represents an intermediate form in-between the simple cells of microbes, and the complex cell types of eukaryotes," Ettema added.
"[W]e found that Loki shares many genes uniquely with eukaryotes, suggesting that cellular complexity emerged in an early stage in the evolution of eukaryotes," said Anja Spang, researcher at Department of Cell and Molecular Biology, Uppsala University, and one of the lead-authors of the study.
The name Lokiarchaeota is derived from the hostile environment close to where it was found, Loki’s Castle, a hydrothermal vent system located on the Mid-Atlantic Ridge between Greenland and Norway at a depth of 2,352 meters.
"Hydrothermal vents are volcanic systems located at the ocean floor. The site where Loki is [is] heavily influenced by volcanic activity, but actually quite low in temperature," said Steffen Jørgensen from the University of Bergen in Norway, who was involved in taking the samples where Loki was found.
"Extreme environments generally contain a lot of unknown microorganisms, which we refer to as microbial dark matter," said Jimmy Saw, researcher at Department of Cell and Molecular Biology, Uppsala University, and co-lead author of the paper.
By exploring microbial dark matter with new genomics techniques, Thijs Ettema and his team hope to find more clues about how complex cells evolved.
"In a way, we are just getting started. There is still a lot out there to discover, and I am convinced that we will be forced to revise our biology textbooks more often in the near future," said Ettema. ®