The bed of the northern Atlantic Ocean is home to a previously unknown group of microorganisms that scientists suppose to be a link between the first simple cells and complex creatures, including human beings.
A team of Norwegian and Swedish scientists have recently
discovered a group of microorganisms called Lokiarchaeota – or
Loki – that may help them understand how primitive microbes
developed into complex cell organisms or eukareotes, ranging from
plants to animals including people.
Their findings, were published in the journal Nature on Wednesday.
Complex #archaea that bridge the gap btwn prokaryotes & eukaryotes. #Protists#Eukaryogenesis. http://t.co/dXO4vEvDj1pic.twitter.com/OpY1EtN85g
— Lukas Novak (@animalculum) May 6, 2015
Loki microorganisms were found on the seabed about 2.35 km from
the surface of the ocean between Norway and Greenland, some 15 km
from Loki's Castle – a field of active hydrothermal vents, named
after one of the gods from Norse mythology.
Loki, the newly discovered type of archaea, which is a group of
single-celled microorganisms, still share over 100 genes with
eukaryotes. Those genes are responsible for such functions as
deforming cell membranes. According to evolutionary
microbiologist Lionel Guy of Sweden's Uppsala University, these
genes could have been “a ‘starter-kit’ to support the
development of cellular complexity”.
READ MORE: Dead zones: Places where no animal can survive found in Atlantic Ocean
"Humans have always been interested in trying to find an
answer to the question, 'Where do we come from?' Well, now we
know from what type of microbial ancestor we descend," Thijs
Ettema, Uppsala University evolutionary microbiologist and
coordinator of the study, told Reuters.
"Essentially, Lokiarchaeota represent a missing piece of the
puzzle of the evolution from simple cells - bacteria and archaea,
prokaryotes – to complex cells – eukaryotes, which includes us
humans," Ettema added.
While microbial life on our planet appeared about 3.5 billion years ago, the first complex cellular creatures emerged approximately 2 billion years ago. According to the authors of the study, “The origin of the eukaryotic cell remains one of the most contentious puzzles in modern biology.”
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— Universitetet Bergen (@UiB) April 15, 2015
Microbiologist Steffen Jørgensen of Norway's University of Bergen
told Reuters that the Lokiarchaeota were discovered during
voyages of a Norwegian research vessel. The oxygen-starved
sediment layers were “desolate, pitch dark and around the
freezing point”.
"Ettema's team have certainly thrown the cat among the
pigeons," Anthony Poole at the University of Canterbury in
New Zealand, told New Scientist news magazine. "It's still
100 per cent archaeon, but the presence of genes we usually
associate with eukaryote cell biology is absolutely
fascinating."