IIt is not uncommon for a new species to be discovered among existing collections; However, it is rare that a new species is still alive. But that's exactly what a research team from Charles University in the Czech Republic discovered when they examined an old culture of marine microorganisms.
In a sample from many years ago, the larger organisms had died out, but one tiny, strange-looking creature was still alive. It was a tiny, single-celled protist, a general group that includes eukaryotic organisms that are not plants, animals or fungi. Their new find, with ray-like projections extending from a central mass, resembled the sun, so the team called it Solarion Arienapublishing your conclusions V Nature.
The curious structure and robustness of the newly discovered species were striking, but genetic analysis revealed S. arienae was hiding even more stunning surprises. After sequencing the genome and cross-referencing existing databases, the researchers determined that the organism did not belong to any previously recognized lineage of eukaryotes. Instead of, S. arienaealong with a handful of other enigmatic protist relatives, they formed a new supergroup called Disparia. A search of environmental DNA databases revealed S. arienae (somewhat paradoxically) both rare and widespread, living a quiet life in marine sediments.
Even more surprising was the presence of DNA inside. S. arienae mitochondria. These organelles contained the gene secAa fragment of a protein translocation system inherited from the bacterial ancestor that gave rise to mitochondria, and a sequence that has been lost in almost all other eukaryotic species. According to the endosymbiotic theory, mitochondria were once free-living prokaryotic cells that were absorbed by the precursors of eukaryotic cells. Following this close interaction, eukaryotic cells developed mitochondria, which provided the energy for the partnership and led to the large number of eukaryotes we see today.
Read more: “The unique fusion that made you (both sheep and yew)»
In other words, S. arienae It is essentially a living fossil, giving researchers unprecedented insight into the evolution of eukaryotic life.
“Solarion is a remarkable reminder of how little we still know about the diversity of microbial life,” said study authors Ivan Cepicka and Marek Walt. statement. “The discovery of such an evolutionarily deep lineage—essentially a living fossil—shows that key parts of eukaryotic history remain hidden in places we rarely explore.”
Scientific discoveries that change the tree of life: Always the last thing you look at.
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Main image: Charles University.
