A new form of life was created by scientists at Groningen University in the Netherlands. Thus, they refuted the hypothesis of the origin of archaea and bacteria from a single unicellular ancestor through the rupture of the plasma membrane. This new life form combines the signs of both organisms.
The study has been published in the journal Science Alert.
The last universal common organism or LUCA
The presumed unicellular ancestor LUCA lived on Earth about 3.5-3.8 billion years ago. The researchers consider it was a single-celled organism with circular DNA, as in bacteria but which was not enclosed in the nucleus, as in eukaryotes.
The biological properties of the ancestor organism were derived from a comparison of the genomes of modern living beings. In this regard, scientists identified 355 genes, which were sure to be available from the LUCA, thus proving that the organisms from Earth have a common unicellular ancestor.
The new life form combines membranes of both bacteria and archaea
Bacteria and archaea are distinct in a variety of characters, including phospholipids, which are part of their cell membranes. They are mirror isomers with identical chemical composition but with a structure that can not be combined.
LUCA, therefore, should have both types of membranes. Later, it divided and each of the parts began to develop in its own way.
However, the new life form, a unicellular organism, showed that the membrane combining lipids of two the types is stable and can not break. Hence, the mechanism of the organism’s formation continues to remain unknown.
Most scientists agree that all living creatures on Earth were once formed from one single organism.
Therefore, the scientists decided to continue working on the new life form hoping to understand the mechanisms of the ancestor organism’s formation and to evidentiate how all the life forms on the planet Earth were formed from one single type of unicellular organism.