It is believed that life on earth originated more than about 3.5 billion years ago but about 2 billion years ago it began to evolve into two broad branches, 'prokaryotes' like the simple cells of bacteria and the 'eukaryotes' with complex cells containing a nucleus and other intricate internal structures. Until now the cell division between the simple cells of microbes such as bacteria from the more complicated cells of animals and plants has been so abrupt and absolute that it was difficult to see how one could have evolved from the other. However, Uppsala University scientists have now discovered the 'missing link' between the two main life-forms. They found a new species of microbes that can explain evolution of organisms with complex cells from single-celled organisms.
During the study, the researchers found a new organism with the genes of both groups. It was found in sediment samples retrieved from the seabed about 10 kilometers (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 meters.
Team leader Thijs Ettema said, "We've identified an organism that seems to represent a very distant cousin of humans and in doing so it tells them something about their own dark past. We are looking at the origin of complex life which occurred sometime after the origin of life itself. This discovery puts the origin of complex life in the spotlight."
The study was published in Nature.