Eukaryotes: A new discovery of life and its Origin

macro_micro organism

A new discovery of life and it’s origin has been discovered according to researchers. New research reveals a crucial moment in the formation of eukaryotic cells, the moment they incorporated mitochondria into their structure. Eukaryotic cells appeared on Earth 1.7 billion years ago, and they are the basis of life based on oxygen, that is, the basis of which the Earth became the only known place in the universe inhabited by birds, grass, mushrooms and humans

Before there were bacteria. About 3.7 billion years ago, the first living beings, archaic bacteria, appeared on Earth. It took a biological prodigy for more complex cells to appear, eukaryotes, which are the origin of all living beings that have existed and exist. Without them, the planet today would be the residence of millions of conglomerates of bacteria, and nothing else.

They appeared on Earth approximately 1.7 billion years ago and their arrival marked what could be considered the most important biological transformation event in the history of life.

A collaborative study, published in Nature , between the groups of Toni Gabaldón, ICREA researcher at the Institute for Research in Biomedicine (IRB Barcelona) and the Barcelona Supercomputing Center (BSC-CNS), and Berend Snel at the University of Utrecht, contributes a little more light on how that extraordinary process took place.

How they started to form

discovery of life: Methanogenic archaea
discovery of lifeMethanogenic archaea like the one in this image are prokaryotic microorganisms that live in strictly oxygen-free environments and obtain energy through the production of natural gas, methane. This is how the first living forms on the planet were

For about the first half of the history of life on Earth, the only discovery of life were relatively simple cells, archaic bacteria. Until the eukaryotes arrived and everything became more complex.

“Eukaryotic cells are larger, contain more DNA, and are made up of compartments, each with its own task,” explains the study’s first author, Julian Vosseberg. “In that sense, you can compare bacterial cells to a tent, while eukaryotic cells are more like houses with multiple rooms.”

How and when organisms changed the tent for a house remains a mystery, since there are no intermediate ways to observe it. But there are some things that are known.

The appearance of eukaryotic cells occurred from anaerobic ancestral organisms approximately 1.7 billion years ago. How did it happen?

There was no serious scientific answer to this fundamental question in the development of life until Lynn Margulis, an American biologist, considered one of the leading figures in the field of biological evolution, proposed, in the 1960s, a revolutionary hypothesis that stated that eukaryotes were the product of a prokaryotic cell that “swallowed” another cell, and thus, a living being forever nested inside another.

Chiristian de Duve, Nobel Laureate in Physiology and Medicine, explains it this way: “endosymbionts (an organism that lives inside another organism.) Were swallowed up by a larger cell, which had already acquired many of the properties that today define eukaryotic cells. Many current eukaryotic cells, leukocytes, for example, engulf prokaryotes. ” And so, joining simple shapes by the powerful effect of phagocytization, everything became more complex.

Mitochondria were once free-living bacteria, and were at some point taken over by the ancestors of today’s eukaryotic cells

Discovery of life: The Arrival of Mitochondria

An important moment in the evolution of this more complex eukaryotic cell was the origin of the mitochondria. Mitochondria are the “power plants” of our cells.

Mitochondria were once free-living bacteria, and were at some point taken over by the ancestors of today’s eukaryotic cells.

The study just published in Nature by Toni Gabaldón, ICREA researcher at the Institute for Research in Biomedicine (IRB Barcelona) and the Barcelona Supercomputing Center (BSC-CNS), and Berend Snel at the University of Utrecht, explains that he has found that a much of the complex cellular machinery had already evolved prior to symbiosis with mitochondria, including the development of transport within the cell and the cytoskeleton.

“Our study suggests that the ancestral host that acquired the mitochondrial endosymbiont had already developed some complexity in terms of a dynamic cytoskeleton and membrane trafficking” says Gabaldón: “this could have favored the establishment of symbiotic associations with other microorganisms, including the mitochondrial ancestor , which eventually integrated into the cell ”.

How did you find this out?

eucariotas
eucariotas

The starting point is that gene duplication (by eating cells from each other) likely drove the increase in cellular complexity, so the researchers tried to reconstruct evolutionary events based on these genetic changes.

“We can use the DNA of contemporary species to reconstruct evolutionary events. Our genes were formed over eons of evolution. They have changed dramatically during that time, but they still have echoes of the distant past, “adds the lead author of the work, Julain Vosseberg:” We have a large amount of genetic material available, from a variety of organisms, and we can use computers to reconstruct the evolution of thousands of genes, including duplications of old genes. These reconstructions have allowed us to discovery of life the timing of important intermediate steps in eukaryotic cells.

As they have shown: “the symbiosis was not a catalyst event for everything else. We observed a spike in gene duplications much earlier in time, indicating that cell complexity had already increased before then, ”says Berend Snel.

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