The origin of the eukaryotic cell remains one of the most contentious puzzles and a major missing link in biology until recently when a team of scientists announced the discovery of just such a transitional form at the bottom of the Atlantic.
Based on a meagre spoon-ful of sample provided by a fellow scientist, Thijs Ettema of Upssala University in Sweden, found the species of archaea most closely related to eukaryotes that lived in the deep seafloor, unfolding the missing link that biologists were looking for since the 1970s.
It was found when Steffen L. Jorgensen, a microbiologist at the University of Bergen, had been digging up sediment 2 miles below the Arctic Ocean and he offered Ettema some of it to probe more closely.
In it, they found microbes that have many features previously found only in eukaryotes.
These microbes, progenitors of complex cellular organisms, showed the biologists the nature of the putative archaeal ancestor, which they described ‘Lokiarchaeota’, named for a hydrothermal vent called Loki’s Castle, a location near where the archaea were found.
The location was about 10km (6.2 miles) away from a volcanic hydrothermal vent called Loki’s Castle situated in the mid-Atlantic between Greenland and Norway at a depth of 2,352 metres.
“Our results provide strong support for hypotheses in which the eukaryotic host evolved from a bona fide archaeon, and demonstrate that many components that underpin eukaryote-specific features were already present in that ancestor,” wrote Ettema and his team in their paper published in the journal Nature.
“Ever since I was a Biology student, I have been intrigued by the origin of the eukaryotic cell – How could something this complex emerge from ‘simple’ cells from Bacteria and Archaea? Even today, the birth of the eukaryotic cell remains one of the biggest enigmas in modern Biology. My current aim is to gain a more profound insight in the evolutionary process of eukaryogenesis using modern genomics approaches with a strong focus on prokaryotic genome evolution and diversity,” says Ettema on his official blog.