Update the theory of evolution? Shaoyan Archae was discovered, blurring the boundaries between cells and viruses – Passionategeekz

Passionategeekz On June 19, Science magazine published a blog post on June 13, reporting that the team of the University of Tokyo in Japan discovered the mysterious microorganism of “Sukunaarchaeum”.Its genome contains only 189 protein-encoded genes, almost all of which are used for their own DNA replication, thus blurring the boundaries between cells and viruses.

When the University of Tokyo team was studying the marine dinoflagellate Citharistes regius, it unexpectedly discovered that there was an abnormal circular DNA in its cells, with only 238,000 base pairs, which is only 5% of the E. coli genome.

It was initially suspected to be experimental error, but after multiple sequencing verifications, it was confirmed to be a novel microorganism. The team then used the Japanese myth of Sukuna-biko-na as inspiration and temporarily named it “Sukunaarchaeum”.

Passionategeekz Note: A very important little god in Japanese mythology, who is usually described as a short god who co-created Japan with the god of Ōkuninushi (Ōkuninushi) and is considered to be the god in charge of medicine, winemaking, magic and knowledge.

The microorganism is parasitized in dinoflagellate cells, and its genome size is even smaller than the smallest archaeological genome recorded previously, but does not carry any known metabolic function genes.

In the genome of “Shaoyan Archae”, more than 95% of the genes focus on DNA replication, transcription and translation, and rely almost entirely on the host to provide life molecules such as amino acids and nucleic acids, forming a “one-way exploitation relationship.”

Although its ability to replicate DNA independently is different from viruses (viruses need to hijack the host mechanism), its strategy of “self-proliferation as the only goal” is highly converging with viruses. Researchers pointed out that it may be the most sterile microorganism known to have metabolic capacity, and cannot even synthesize the protein building blocks needed for its own survival.

This discovery shakes the definition of “life forms” in traditional biology. Kate Adamra, a synthetic biologist at the University of Minnesota, believes that the “Shaoyan Archae” may be a “living fossil of evolution”, revealing the potential path for archaea to evolve into viruses.

But San Diego State University biologist Elizabeth Waters is cautious and says more evidence is still needed to directly assert that it is the “predecessor of the virus”. In any case, the genome simplification of the microorganism provides a unique sample for studying how life loses function in evolution, or even “degenerates into viruses.”

The team is trying to observe through electron microscope Sukunaarchaeum cellular morphology (presumably less than 1 micron) and analyze how its membrane-related proteins interact with the host.

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