Loki: Missing Link Between Simple Cells And Eukaryotes Found

Scientists have discovered a new microorganism that they believe is the missing link between simple prokaryotic cells and complex life forms such fungi, plants and animals, including humans. It would help them solve the puzzle of how complex cellular life evolved from simple cells.

Loki: Missing Link Between Simple Cells And Eukaryotes Found


Loki may help solve the puzzle of complex cellular evolution

Researchers led by Anja Spang of Uppsala University in Sweden found a microbe called Lokiarchaeota, or Loki for short, about two kilometers deep in the Atlantic Ocean between Norway and Greenland. It was named Loki after the hydrothermal vent system Loki’s Castle, near which it was found. For over a century, scientists have been puzzled by the question as to how life evolved from simple cells into the overwhelming diversity of complex organisms.

The scientific community believes that complex eukaryotic life forms emerged about two billion years ago. Lokiarchaeota is part of the Archaea group that lack internal structures such as a nucleus. Archaea and bacteria are together called prokaryotes due to their simple cellular structure. Thijs Ettema, a co-author of the study, said they couldn’t believe their eyes when they obtained first results of the study.

Loki had the ‘starter kit’ to support cellular complexity

Loki’s genome represented an intermediate form in-between the simple cells and complex life forms. Researchers further confirmed it after placing it in the Tree of Life. Despite being part of the Archaea group, it shared many genes uniquely with eukaryotes, many of them related to the cell membrane. It suggests that cellular complexity emerged in the early stage of evolution of eukaryotic life forms.

Evolutionary microbiologist Lionel Guy said these genes might have provided Loki with a “starter kit” to support cellular complexity. Evolution from prokaryotic to eukaryotic life forms is one of the greatest transitions in the history of life on our planet.

Loki was discovered close to the hostile environment of a hydrothermal vent, where it is heavily influenced by volcanic activity. Findings of the study were published in the journal Nature.