Scientists Discover Controversial New Organism

Most organisms fit comfortably into standard definitions of “life,” i.e., cells that grow, reproduce independently, and generate energy. Viruses have always been an exception, sitting in a gray area because they cannot function without a host. However, Knewz.com has learned that a newly identified organism, described in a recent study, is now complicating the picture even further. Named “Sukunaarchaeum mirabile,” this microbe displays traits of both viruses and cellular life, prompting new questions about the boundaries of biology.

The Newly Discovered Organism Has Some Characteristics of a Virus

Much like a virus, “Sukunaarchaeum mirabile” offloads certain biological functions onto its host and appears singularly obsessed with replicating itself, according to reports. However, unlike viruses, this cellular entity contains the necessary genes to create its own ribosomes and messenger RNA. According to the research team, led by molecular biologist Ryo Harada of Dalhousie University in Halifax, Nova Scotia, its structure and function place it somewhere between minimal cellular life and virality, a classification that does not comfortably fit into existing biological categories. Scientists believe that its minimalist genetic setup may also reflect an advanced form of symbiosis. By shedding unneeded genes, the organism can maintain a smaller genome while relying on a host to supply its needs. While scientists have seen similar strategies in other symbiotic microbes, Sukunaarchaeum represents one of the most extreme examples known so far.

Scientists Discovered the Organism While Studying Plankton

According to reports, the organism was discovered during a genetic study of Citharistes regius, a species of marine plankton. While analyzing DNA sequences, the scientists came across a circular DNA strand that didn’t match any known organism. After deeper analysis, they determined that the unknown DNA belonged to a new species within the domain Archaea, which are a group of single-celled organisms that are genetically distinct from bacteria and are known for surviving in extreme environments. However, this particular archaeon was found in the ocean, living in association with plankton. It is worth noting that although archaea are associated with prokaryotic cells, eukaryotic cells (like human beings) ultimately descended from them a couple of billion years ago.

The Smallest Genome Ever Recorded in an Archaeal Organism

With only 238,000 base pairs of DNA, Sukunaarchaeum has the smallest genome ever recorded in an archaeal organism, less than half the size of the previously smallest known archaeal genome. “Its genome is profoundly stripped-down, lacking virtually all recognizable metabolic pathways, and primarily encoding the machinery for its replicative core: DNA replication, transcription, and translation,” the authors wrote. “This suggests an unprecedented level of metabolic dependence on a host, a condition that challenges the functional distinctions between minimal cellular life and viruses,” the paper added. The researchers named it Sukunaarchaeum mirabile after Sukuna, a small-statured figure from Japanese mythology. Although classified as an archaeon, its dependence on a host and its stripped-down genome make it more similar to viruses in how it functions. It straddles the boundary between being a living cell and a dependent, parasitic agent.

More Organisms Like This May Exist

The researchers suggest that more organisms like this may exist, hidden in genetic data or living within symbiotic ecosystems that have not yet been studied closely. By continuing to explore these environments, scientists may uncover additional life forms that further test the limits of how life is defined. In the words of the study authors, Sukunaarchaeum “pushes the conventional boundaries of cellular life and highlights the vast unexplored biological novelty within microbial interactions.”

The researchers noted, “Further exploration of symbiotic systems may reveal even more extraordinary life forms, reshaping our understanding of cellular evolution.”

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