Scientists discover new entity that exists between life and not life

We tend to think something is either alive or not – unless we’re discussing Schrödinger's cat. For something to be considered alive, we often think of anything that can reproduce, produce its own energy and have homeostasis – from humans, to animals, to plants and even single-celled organisms. However, the challenge comes when trying to define a virus. They don’t grow, or reproduce on their own, nor can make their own energy. But when it infects a host, they can do some pretty population-altering things, as we saw with Covid. Now, researchers from Canada and Japan have found something virus-like, but more ‘alive’ (Picture: Getty Images)

What is a virus?

Since viruses were first discovered in 1892 by Dmitri Ivanovsky, their definition has varied from poisons to biological chemicals. However, scientists initially believed that viruses were living organisms, although simple, because they caused diseases, like bacteria – which we know to be alive. But they don’t have any metabolic processes, and can’t make any proteins by themselves. They can only make copies of themselves after they have invaded another organism, and can only live outside their host in certain environments, but their life span is much shorter, which is why some scientists deem them as non-living (Picture: Getty Images)

So, what’s this new thing?

The researchers named the new entity as Sukunaarchaeum mirabile, named after a Japanese mythological deity known for its small stature. But what makes it strange is that this new entity has the required genes to create its own ribosomes and messenger RNA. This is something viruses don’t normally contain. However, it is like a virus in the way that it offloads some biological functions onto its host and is dedicated to replicating itself (Picture: Getty Images)

The authors wrote in their yet to be peer reviewed paper on bioRXiv: ‘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. This suggests an unprecedented level of metabolic dependence on a host, a condition that challenges the functional distinctions between minimal cellular life and viruses’ (Picture: Getty Images)

How did the team find Sukunaarchaeum mirabile?

The team said they chanced upon this strange creature while studying the bacterial genome of Cithgaristes regius, a bacterial genome of the marine plankton. Dr Ryo Harada and his team discovered a loop of DNA which did not match any known species. They eventually figured out that it belonged to a domain known as Archaea – a domain of life from which our group, eukaryotes, evolved (Picture: Getty Images)

The Sukunaarchaeum mirabile is strange in other ways too. The smallest known archaea has 490,000 base pairs of DNA –  the nucleotide bases that form the ‘rungs’ of the DNA double helix. But some viruses can reach into millions of base pairs. However, the Sukunaarchaeum mirabile only has 238,000, meaning it has less than half the number of base pairs of even the smallest archaeal (Picture: Getty Images)

They said: ‘The discovery of Sukunaarchaeum pushes the conventional boundaries of cellular life and highlights the vast unexplored biological novelty within microbial interactions, suggesting that further exploration of symbiotic systems may reveal even more extraordinary life forms, reshaping our understanding of cellular evolution’ (Picture: Getty Images)