For all the folks saying, "Isn't this just a virus?"
The actual paper states that the genome encodes transfer RNA's and ribosomal RNA's. I think that's a really important biological distinction missing from the popular press junket. The primary source material is well written and elucidates a lot more than the Quanta article. https://www.biorxiv.org/content/10.1101/2025.05.02.651781v1
That’s interesting. The main difference seems to be that those other tiny organisms only encode how to produce some metabolic products for the host but cannot reproduce independently, so they are quite close to being organelles. Instead, this new one pretty much only produces the proteins it needs to reproduce and nothing for the host.
The new one with 238 kbp:
> Sukunaarchaeum encodes the barest minimum of proteins for its own replication, and that’s about all. Most strangely, its genome is missing any hints of the genes required to process and build molecules, outside of those needed to reproduce.
Referencing the 159 kbp one:
> However, these and other super-small bacteria have metabolic genes to produce nutrients, such as amino acids and vitamins, for their hosts. Instead, their genome has cast off much of their ability to reproduce on their own.
Still far, far too complex to occur "randomly," which is fascinating. The odds of 112k bases arranging in any meaningful way by chance within a membrane are the kind of thing you wouldn't get if you ran a trillion trillion trillion universes.
There's many hypotheses, basically all different variations on "soup of organic compounds forming complex catalytic cycles that eventually result in the soup producing more similar soup, at which point it begins to be subject to differential selection." It's a reasonable idea but where did this happen, and do the conditions still exist? If we went to that place would it still be happening?
There's reason to believe the answer would be no because modern lifeforms would probably find this goo nutritious. So life may have chemically pulled up the ladder from itself once it formed.
This of course assumes no to more fanciful options: panspermia that pushes the origin back to the beginning of the cosmos and gives you more billions of years, creation by a God or some other kind of supernatural or extra-dimensional entity, etc.
1. Autocatalytic RNA reaction networks -- "soup producing more soup" -- are easily replicated in the lab, subject to Darwinean processes, and are at the center of ongoing study. "0 to Darwin" is now easy, "Darwin to Life" is the new focus, and God of the Gaps must retreat once again.
2. Spores hitchhiking on impact ejecta sounds exotic until you realize that anywhere life is present at all spores will be everywhere and extremely sturdy. That desktop wallpaper you have of planets crashing together and kicking off an epic debris cloud? Everything not molten is full of spores.
3. Religious explanations are not in the same universe of seriousness as 1 and 2. Opening with a religious talking point and closing with a false equivalence is mega sus.
Panspermia is pretty much irrelevant to the actual question though; even assuming life got to Earth the hitchhiker way, it would have to have developed on another planet, and we’re back to square one.
Not to mention the constant trickle of "X survived in space" stories that we get every time someone bothers to collect and culture a sample. The amount of success at every stage with, frankly, very little effort spent tuning the conditions, multiplied by "bacteria are everywhere" makes hitchhiking less crazy than it sounds. Our intuition misleads us because bacteria are so much better at handling acceleration (easy if you're small) and dessiccation (everywhere is a desert if you're small) than anything we are used to thinking about.
Good news: the primordial oceans were so vast (literally planet-scale) and persisted for so long (millions to billions of years) that you can run a trillion trillion individual random reactions.
You are being severely restricted by your imagination. You seem to have presupposed that random abiogenesis is impossible and reconstructed the facts to support that claim because you can't conceive of the alternative.
Planets are really, really big. Any one chemical reaction is on the scale of molecules. If you let those figures compound for a long time, the number of total reactions gets very, very large. Far larger than you imagine. Many times more.
The probability space of a 140-nucleotide chain is 10^84. The estimated number of atoms in the universe is 10^80. The hypothesized RNA self-replicator is far simpler than the 238,000 base pair archaeal genome. But how are they formed? Even the most favorable prebiotic lab conditions have only produced short nucleotide chains. Direct chemical synthesis only recently achieved chains over 1700 nucleotides long [1].
>Still far, far too complex to occur "randomly," which is fascinating
I don't see the word "random" anywhere in the article. By random maybe you mean it's seemingly indeterministic? Regardless of the nature of the underlying process, at the classical level, the environment acts as a deterministic filter, ie, other chemical processes.
If you’re interested in this area I highly recommend “The Vital Question” by Nick Lane if you haven’t read it.
The TLDR of his theory is that life originated in alkaline hydrothermal vents on the ocean floor, where natural energy gradients could have driven primitive metabolic reactions before the development of DNA.
Book goes into a lot of layperson-accessible detail.
> Still far, far too complex to occur "randomly," which is fascinating
Why spend time making this point? Nobody believes that this occurred randomly: it occurred via evolution.
The mutations are a random part of evolution, but the process overall is not random at all - no more so than your immune system (which randomly generates antibodies, then selects against those that target innate epitopes), or stable diffusion (which starts with random noise, then marches up a gradient toward a known target).
It is the selection step that makes similar processes non-random, because a random selection step would just be noise.
This is technically random. The entire creationist argument is that complexity cannot come from randomness but evolution is the method in which it does.
Evolution is just a sort of way for low entropy structures to form from randomness. It’s still random all the way down.
The man is just trying to reconcile a belief in god with the scientific reality. He needs to bend the evidence to fit his identity he cannot bend his identity to fit the evidence because that could break his identity. The fact he commented here on this topic is sort of unhinged. It seems like the article presented evidence that is strikingly against his world view and he needed to justify something in order to prevent his identity from rearranging itself according to external reality.
The entire fossil record and the mountains of shared DNA between very different creatures is pretty compelling evidence. Not to mention the idea of changing 'kinds' is an entirely human-derived categorisation, not something that has some natural definition.
"Change kinds" is something that only people who believe in a rather literal view of the Christian bible say, and only because that's the popular fundamentalist argument against evolution.
Fundamentally, it's impossible to reconstruct something from the fossil record that's convincing to these folks, because they will always arbitrarily decide "fossil 1 is kind X, and fossil 2 is kind Y, you need to find me fossil 1.5," no matter how close in time and likeness the fossils are.
So what they actually want is "evolve a lizard species into cats" which fundamentally misrepresents both A) how evolution works (it does not concern itself with human categories) and B) the vast timescale over which small changes accrue.
"Kinds" are just human categories we've mapped onto the results of billions of years of evolution after the fact.
"It's all random all the way down" is just another religious belief. Besides, has anyone estimated the probability of creating organisms so complex using this random evolution scheme? Another problem is why would randomly-evolved organisms be so geometrically symmetric? I'd expect a random process to create an unholy blob of matter.
You're lacking imagination and understanding of how these systems form. Symmetry is very commonplace in nature, for very unsurprising reasons, because what's random is how the processes that create those forms change over time, not the entirety of those processes themselves. And yes, there is a huge amount of study of how life could form in the kinds of environments we think existed on earth near the start of life. ATM it's not so much 'how could this happen at all' and more 'what looks like the most likely way that it happened'.
The point I was making was that the complexity curve has to meet the floor at some point, and thinking about how this happens and what that looks like is interesting.
I was familiar with RNA world but wasn't aware of how much progress had been made.
Isn't replication the single most important act of metabolism for an organism? I am trying to reconcile their ""lost genes include those central to cell metabolism, meaning it can neither process nutrients nor grow on its own" with their "The organism’s “replicative core” — the genetic components needed to reproduce itself — remains, making up more than half of its genome".
Replication (making DNA, RNA, and proteins, and ultimately dividing) is a highly energy-intensive and material-intensive process. What appears to be lost by Sukunaarchaeum are the genes to build basic building blocks (amino acids, vitamins, nucleotides) from scratch. It cannot find a sugar molecule and break it down for energy (it can "neither process nutrients nor grow on its own"). Yet it can take pre-made energy and building blocks and assemble them into a new organism.
What is the exact line between the host's metabolic contribution and the archaeon's replicative assembly? How "finished" are the raw materials that the host provides, and how does the archaeon's extremely reduced genome still manage the subsequent steps of self-replication?
You could argue the same way for a lot of parasite species, many of which are ridiculously more complex. Is a complex multicellular organism (an animal even) not alive because it needs to get some component needed for its reproduction from another species? If you get hung on such specific components, where do you draw the line?
So in this sense then, human beings themselves are obligate metabolic parasites on the planetary ecosystem, particularly on other life forms (plants, animals, microbes). The term "parasite" here is used in the metabolic sense of relying on another organism to produce essential compounds one cannot produce oneself. The molecules we must obtain fully synthesized from our diet are called essential nutrients. And for a Sukunaarchaeum, everything is an essential nutrient.
Are there any animals which don’t need components from another organism? Isn’t heterotrophy one of the notable attributes of Animalia? There are the infamous sea slugs which eat algae then use the algae’s photosynthetic chloroplasts to photosynthesize the chemical energy they need, but they still need the algae to make those chloroplasts.
As I understand it, it's not so much that they got "hung up" on some specific capabilities for theoretical reasons, but that it's rare to find cells without these capabilities. In other words, it's nature that seemed so "hung up" on these things.
You could make a distinction here in that we only need raw materials, we don't need another organism to reproduce. Mosquitos can also easily consume raw materials in the form of nectar to survive, but they need to take blood from other animals if they want to reproduce. If you go along this chain of thought, you can come up with arbitrary definitions.
We need 20 different amino acids to build all our proteins. We can synthesize 11 of them (non-essential amino acids), but we must obtain the other 9 Essential Amino Acids fully formed from the food we eat.
I wonder if this minimal cell could be described instead as something between a bacteria and a virus. I am not a biologist, but IIRC viruses penetrate cells then hijack the cell's standard machinery to replicate itself, until the cell explodes; sort of like a DNA/RNA injection exploit.
Life's two most fundamental properties are homeostasis and reproduction. The loss of these two combined with its parasitic nature makes this cell a form on non-life.
No life exists "by themselves". Self-replication means using only its own DNA and not mangling with other's. Virii are not only parasites but dead matter (a ribonucl molecule surrounded by proteins that happens to stick to other cells, like dirt on the skin). Gut microbioma is parasite.
There is another life property that this object does not fulfill and is called Teleonomia, that is governed by an ultimate goal.
> the bacterium Carsonella ruddii, which lives as a symbiont within the guts of sap-feeding insects, has an even smaller genome than Sukunaarchaeum, at around 159,000 base pairs
159 000 base pairs is ~320 Kbit, or 40 KBytes. I wonder, if that is the minimum size of a cell firmware. Also, if the cell is that simple, can we study it exhaustively and completely? Like, decipher every base pair in DNA, and determine what it is responsible for. And make an interactive website for that.
> ... we report the discovery of Candidatus Sukunaarchaeum mirabile, a novel archaeon with an unprecedentedly small genome of only 238 kbp —less than half the size of the smallest previously known archaeal genome— from a dinoflagellate-associated microbial community.
Atoms and sub-atomic particles fit this definition.
Machines fit this definition.
Fire fits this definition.
Truth is "life" is not a distinct category. We just think of life as complex life. A complex system that mines energy gradients to preserve and replicate its forms.
But there's no hard boundary. It's just in our head.
People always come up with people-centric definitions. They need to be updated based on what are the fundamental characteristic of something that is alive.
The current, more standard definition, seems to be based on metabolism. I disagree and argue for reproduction and evolution.
I think the genome might be mostly just the "config file". So the cell already contains most of the information and mechanisms needed for the organism. The genome is config flags and some more detailed settings that turn things on and off in the cell, at specific times in the life of the organism. From this point of view, the discussion about how many pairs/bytes of information are in the genome is misleading. Similar analogy: I can write a hello world program, which displays hello world on the screen. But the screen is 4k, the windows background is also visible, so the hardware and OS are 6-8 orders of magnitude more complex than the puny program, and the output is then much more complex than the puny program.
I’ve been thinking about a wild theory regarding the incredible biological complexity we see in mammals today.
What if our bodies (apart from the brain) are actually the result of an ancient aggregation of once-separate "organisms" that evolved to live symbiotically?
Over millions of years, their DNA might have fused and co-evolved into a single, unified genome. What began as cooperation between distinct life forms could have gradually become inseparable, giving rise to the intricate multicellular systems we now take for granted.
It's called Symbiogenesis [0] and it's not at all a wild theory. But it's limited to cell components, not multiples organs fusing to create something as complex as a mammal.
Also, as others have noted, your idea is not necessarily wild. Certainly, at the sub-cellular level, there is tremendous evidence that symbiosis played a part in creating "higher level" organisms (i.e., eukaryotes).
Many genomes are like a junk-yard with fossilized relics of infectious agent nucleic acid (e.g., viruses), etc. Apologies for the junk-yard / fossil mixed metaphor.
This isn't a wild theory or a novel one. It's well-established that endogenous retroviruses alter DNA and are inherited. In addition to the primary genome being modified this way, all mitochondria are symbiotic organisms inside plant and animal cells, with their own DNA, and are vital to life. Same thing for chloroplasts in plants. And then there are gut bacteria, which are vital to life, symbiotic, and directly influence evolution and the genome.
I believe that we’re living in that situation now. I don’t think life can be divided into smaller organisms. That there is just one complex life that we failed to see based on our past prejudice.
What is this, some content creator run Biohacker Lab in some basement on Microflix premises?
Ominous voice: the tiny cell withdrew into the cracks of existence and saved it's entire code to be in the lines between, the Singular Point which was neither a fraction of space, nor a unit of time, hidden in the void of Chututululu's (33rd degree cousin of Cthulhu) dreams, written in the unspeakable language of the subtext of the book of neither life nor death, that nobody would decipher until the time was right AND GODZILLA GETS TO WALK THE EARTH AGAIN.
This is cool but doesn't say much about the definition of life IMO. They're obligate parasites. This isn't a new category. They're still eating stuff from their host (probably, given the caveat later in the article), and still using it to replicate, it's just a more limited diet.
They aren’t. Apart from DNA replication, transcription, and translation, their genome lacks elements encoding for even the most simple metabolic pathways.
Then where are they getting the materials to replicate? Where are they getting the energy? Magic? No, they're pulling pre-metabolized materials and energy from the host.
Only if it has a mechanism to send signals into the host and cell. For the CEO metaphor to hold, I'll accept that these signals can be entirely ignored, but they need to be transmitted.
What do you mean? The interaction described in the article is just of the small cell stealing nutrients from the host's pouch. That seems like enough of a "point" for the parasitic cell, while giving it zero incentive to advertise its presence with signals.
Reminds me of how the discovery of giant viruses - like truly huge viral particles - was immediately also followed by discovering "virophages" which parasitized them.
Which of course makes sense to some degree: if an adaptive strategy is successful enough, then parasitizing something which successfully implements it is going to be resource favorable (and likely, presumably by being a member of that species and just shedding components you don't need if you take them).
I don’t think a precise definition of life is particularly important or of particular interest to most biologists. This thing is life in the sense that it’s definitely in scope of being studied by biologists (same is true for viruses, of course). And the reason it is speculated that it may be crucial to understanding life is mentioned in the article: “This organism might be a fascinating living fossil—an evolutionary waypoint that managed to hang on.”
I don't think that they are. The term life, as it's currently defined, is not very useful. The reality is that there is a very colorful spectrum of microscopic biology and that a single bin of "alive" and "not alive" is like trying to paint the mona lisa with a single pixel.
This scishow video gives a good look at the tip of the iceberg.
Maybe better to say "We understand enough physics to model all the possible interactions PHYSICS might have on this planet".
There are many levels of abstraction between quantum/particle physics and life, or even just cosmology (things like dark matter, etc), that we really know very little about.
Virus are simpler and have challenged the definition of life for a long time already. This article excludes virus from life because they lack ribosomes.
Last time I checked, they are considered "not alive" when outside of a host, and "alive" when inside a host.
About size:
"Genome size varies greatly between species. The smallest—the ssDNA circoviruses, family Circoviridae—code for only two proteins and have a genome size of only two kilobases;[61] the largest—the pandoraviruses—have genome sizes of around two megabases which code for about 2500 proteins"
The definition of life is also uninteresting. At its core it is just a vocabulary and classification issue. We humans invented the word life and we humans chose to make the word vague, confusing and differently defined among different people. An arbitrary vocabulary and definitional choice for a word “life” is not in actuality interesting to think about.
Yet people get hung up about it as if it’s a philosophical problem. It is not a philosophy problem. The word is loaded and you’re simply spending an inordinate amount of time trying to define some made up boundary of what fits this category you made up. It is a communication problem disguised as deeper.
Life is the process of decreasing entropy. If they stick with that definition, they’d be fine. And they’d find out that life is even more abundant than they can imagine.
This is one of those things that sounds profound, but only until you think about it. Depending on how you read this, it either excludes life entirely or includes all sorts of things that are not meaningfully alive.
1. Living things locally decrease entropy but globally increase it.
2. Many other processes do the same. As chermi noted, a liquid solidifying has the same characteristic.
I definitely choose the second of your two outcomes. That it includes all sorts of things that you think are not meaningfully alive. But these things are actually life.
Yes, living things locally decrease entropy and that’s my point.
And maybe I should’ve been more clear for people who cannot grasp new understandings, anything that can decrease its own entropy is living.
I mean, do you think life has nothing to do with the organization matter into a lower entropy state?
Water does not decrease its own entropy. If you can’t understand the distinction I’m making then you do not have the imagination and creativity to create new understanding.
A glass of water in a cold environment radiates away heat until it freezes, decreasing its local entropy and increasing global entropy.
> If you can’t understand the distinction I’m making then you do not have the imagination and creativity to create new understanding.
Perhaps you could explain your distinction instead of insulting people. It’s possible you have some interesting and insightful distinction but as of now you’ve not explained it nor given any examples of this “more abundant” life.
I’m not insulting you. I’m pointing out a reality. You’re reading comprehension is failing you right now.
Water does not freeze itself. That is the distinction. But myself, as a living being, can turn water into ice. And I can create an organize materials inside of my own body.
I pointed out something interesting. The least thing you could do is actually look up to see if there’s any validity or research on what I’m talking about.
By more abundant life, I’m talking about how the definition of life we have is limited, but it’s ever expanding based on the papers of the original post. I’m talking about a greater expansion of our understanding of life that’s discussed in papers that deal with entropy and life.
For all the folks saying, "Isn't this just a virus?"
The actual paper states that the genome encodes transfer RNA's and ribosomal RNA's. I think that's a really important biological distinction missing from the popular press junket. The primary source material is well written and elucidates a lot more than the Quanta article. https://www.biorxiv.org/content/10.1101/2025.05.02.651781v1
Very impressive! To be clear, this is not the smallest known bacterial genome; only the smallest known archaeal bacterial genome, at 238k base pairs.
In the article they mention C. ruddii, with a smaller 159k base pair genome.
But according to wikipedia, it seems N. deltocephalinicola, at 112k base pairs, may be the smallest known bacterial genome. https://en.wikipedia.org/wiki/Nasuia_deltocephalinicola
That’s interesting. The main difference seems to be that those other tiny organisms only encode how to produce some metabolic products for the host but cannot reproduce independently, so they are quite close to being organelles. Instead, this new one pretty much only produces the proteins it needs to reproduce and nothing for the host.
The new one with 238 kbp:
> Sukunaarchaeum encodes the barest minimum of proteins for its own replication, and that’s about all. Most strangely, its genome is missing any hints of the genes required to process and build molecules, outside of those needed to reproduce.
Referencing the 159 kbp one:
> However, these and other super-small bacteria have metabolic genes to produce nutrients, such as amino acids and vitamins, for their hosts. Instead, their genome has cast off much of their ability to reproduce on their own.
A nitpick: Although similar in some aspects, archaea are not bacteria; they are classified under their own phylogenetic domain.
Still far, far too complex to occur "randomly," which is fascinating. The odds of 112k bases arranging in any meaningful way by chance within a membrane are the kind of thing you wouldn't get if you ran a trillion trillion trillion universes.
There's many hypotheses, basically all different variations on "soup of organic compounds forming complex catalytic cycles that eventually result in the soup producing more similar soup, at which point it begins to be subject to differential selection." It's a reasonable idea but where did this happen, and do the conditions still exist? If we went to that place would it still be happening?
There's reason to believe the answer would be no because modern lifeforms would probably find this goo nutritious. So life may have chemically pulled up the ladder from itself once it formed.
This of course assumes no to more fanciful options: panspermia that pushes the origin back to the beginning of the cosmos and gives you more billions of years, creation by a God or some other kind of supernatural or extra-dimensional entity, etc.
1. Autocatalytic RNA reaction networks -- "soup producing more soup" -- are easily replicated in the lab, subject to Darwinean processes, and are at the center of ongoing study. "0 to Darwin" is now easy, "Darwin to Life" is the new focus, and God of the Gaps must retreat once again.
2. Spores hitchhiking on impact ejecta sounds exotic until you realize that anywhere life is present at all spores will be everywhere and extremely sturdy. That desktop wallpaper you have of planets crashing together and kicking off an epic debris cloud? Everything not molten is full of spores.
3. Religious explanations are not in the same universe of seriousness as 1 and 2. Opening with a religious talking point and closing with a false equivalence is mega sus.
Would love to see some sources for #1. #2 sounds plausible but speculative?
Panspermia is pretty much irrelevant to the actual question though; even assuming life got to Earth the hitchhiker way, it would have to have developed on another planet, and we’re back to square one.
RNA World is really cooking: https://pubmed.ncbi.nlm.nih.gov/39358873/
Ejection: https://link.springer.com/chapter/10.1007/3-540-25736-5_3
Reentry: https://journals.plos.org/plosone/article?id=10.1371/journal...
Not to mention the constant trickle of "X survived in space" stories that we get every time someone bothers to collect and culture a sample. The amount of success at every stage with, frankly, very little effort spent tuning the conditions, multiplied by "bacteria are everywhere" makes hitchhiking less crazy than it sounds. Our intuition misleads us because bacteria are so much better at handling acceleration (easy if you're small) and dessiccation (everywhere is a desert if you're small) than anything we are used to thinking about.
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Good news: the primordial oceans were so vast (literally planet-scale) and persisted for so long (millions to billions of years) that you can run a trillion trillion individual random reactions.
You are being severely restricted by your imagination. You seem to have presupposed that random abiogenesis is impossible and reconstructed the facts to support that claim because you can't conceive of the alternative.
Planets are really, really big. Any one chemical reaction is on the scale of molecules. If you let those figures compound for a long time, the number of total reactions gets very, very large. Far larger than you imagine. Many times more.
The probability space of a 140-nucleotide chain is 10^84. The estimated number of atoms in the universe is 10^80. The hypothesized RNA self-replicator is far simpler than the 238,000 base pair archaeal genome. But how are they formed? Even the most favorable prebiotic lab conditions have only produced short nucleotide chains. Direct chemical synthesis only recently achieved chains over 1700 nucleotides long [1].
1. https://www.chemistryworld.com/news/first-direct-chemical-sy...
>Still far, far too complex to occur "randomly," which is fascinating
I don't see the word "random" anywhere in the article. By random maybe you mean it's seemingly indeterministic? Regardless of the nature of the underlying process, at the classical level, the environment acts as a deterministic filter, ie, other chemical processes.
If you’re interested in this area I highly recommend “The Vital Question” by Nick Lane if you haven’t read it.
The TLDR of his theory is that life originated in alkaline hydrothermal vents on the ocean floor, where natural energy gradients could have driven primitive metabolic reactions before the development of DNA.
Book goes into a lot of layperson-accessible detail.
> Still far, far too complex to occur "randomly," which is fascinating
Why spend time making this point? Nobody believes that this occurred randomly: it occurred via evolution.
The mutations are a random part of evolution, but the process overall is not random at all - no more so than your immune system (which randomly generates antibodies, then selects against those that target innate epitopes), or stable diffusion (which starts with random noise, then marches up a gradient toward a known target).
It is the selection step that makes similar processes non-random, because a random selection step would just be noise.
This is technically random. The entire creationist argument is that complexity cannot come from randomness but evolution is the method in which it does.
Evolution is just a sort of way for low entropy structures to form from randomness. It’s still random all the way down.
The man is just trying to reconcile a belief in god with the scientific reality. He needs to bend the evidence to fit his identity he cannot bend his identity to fit the evidence because that could break his identity. The fact he commented here on this topic is sort of unhinged. It seems like the article presented evidence that is strikingly against his world view and he needed to justify something in order to prevent his identity from rearranging itself according to external reality.
I'd like to see some form of evidence that creatures can change kinds, it seems impossible to me, how do you account for that?
The entire fossil record and the mountains of shared DNA between very different creatures is pretty compelling evidence. Not to mention the idea of changing 'kinds' is an entirely human-derived categorisation, not something that has some natural definition.
"Change kinds" is something that only people who believe in a rather literal view of the Christian bible say, and only because that's the popular fundamentalist argument against evolution.
Fundamentally, it's impossible to reconstruct something from the fossil record that's convincing to these folks, because they will always arbitrarily decide "fossil 1 is kind X, and fossil 2 is kind Y, you need to find me fossil 1.5," no matter how close in time and likeness the fossils are.
So what they actually want is "evolve a lizard species into cats" which fundamentally misrepresents both A) how evolution works (it does not concern itself with human categories) and B) the vast timescale over which small changes accrue.
"Kinds" are just human categories we've mapped onto the results of billions of years of evolution after the fact.
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"It's all random all the way down" is just another religious belief. Besides, has anyone estimated the probability of creating organisms so complex using this random evolution scheme? Another problem is why would randomly-evolved organisms be so geometrically symmetric? I'd expect a random process to create an unholy blob of matter.
You're lacking imagination and understanding of how these systems form. Symmetry is very commonplace in nature, for very unsurprising reasons, because what's random is how the processes that create those forms change over time, not the entirety of those processes themselves. And yes, there is a huge amount of study of how life could form in the kinds of environments we think existed on earth near the start of life. ATM it's not so much 'how could this happen at all' and more 'what looks like the most likely way that it happened'.
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People misread my comment as creationism.
The point I was making was that the complexity curve has to meet the floor at some point, and thinking about how this happens and what that looks like is interesting.
I was familiar with RNA world but wasn't aware of how much progress had been made.
Isn't replication the single most important act of metabolism for an organism? I am trying to reconcile their ""lost genes include those central to cell metabolism, meaning it can neither process nutrients nor grow on its own" with their "The organism’s “replicative core” — the genetic components needed to reproduce itself — remains, making up more than half of its genome".
Replication (making DNA, RNA, and proteins, and ultimately dividing) is a highly energy-intensive and material-intensive process. What appears to be lost by Sukunaarchaeum are the genes to build basic building blocks (amino acids, vitamins, nucleotides) from scratch. It cannot find a sugar molecule and break it down for energy (it can "neither process nutrients nor grow on its own"). Yet it can take pre-made energy and building blocks and assemble them into a new organism.
What is the exact line between the host's metabolic contribution and the archaeon's replicative assembly? How "finished" are the raw materials that the host provides, and how does the archaeon's extremely reduced genome still manage the subsequent steps of self-replication?
You could argue the same way for a lot of parasite species, many of which are ridiculously more complex. Is a complex multicellular organism (an animal even) not alive because it needs to get some component needed for its reproduction from another species? If you get hung on such specific components, where do you draw the line?
So in this sense then, human beings themselves are obligate metabolic parasites on the planetary ecosystem, particularly on other life forms (plants, animals, microbes). The term "parasite" here is used in the metabolic sense of relying on another organism to produce essential compounds one cannot produce oneself. The molecules we must obtain fully synthesized from our diet are called essential nutrients. And for a Sukunaarchaeum, everything is an essential nutrient.
Are there any animals which don’t need components from another organism? Isn’t heterotrophy one of the notable attributes of Animalia? There are the infamous sea slugs which eat algae then use the algae’s photosynthetic chloroplasts to photosynthesize the chemical energy they need, but they still need the algae to make those chloroplasts.
As I understand it, it's not so much that they got "hung up" on some specific capabilities for theoretical reasons, but that it's rare to find cells without these capabilities. In other words, it's nature that seemed so "hung up" on these things.
well people want simple models and explanations -- just like physicists want to model cows as "spherical boing boing cows"
We can survive without a constant stream of incoming raw materials. I wouldn’t think that makes us any less alive. Nor are we a parasite on the food.
You could make a distinction here in that we only need raw materials, we don't need another organism to reproduce. Mosquitos can also easily consume raw materials in the form of nectar to survive, but they need to take blood from other animals if they want to reproduce. If you go along this chain of thought, you can come up with arbitrary definitions.
We need mitochondria.
We need 20 different amino acids to build all our proteins. We can synthesize 11 of them (non-essential amino acids), but we must obtain the other 9 Essential Amino Acids fully formed from the food we eat.
I wonder if this minimal cell could be described instead as something between a bacteria and a virus. I am not a biologist, but IIRC viruses penetrate cells then hijack the cell's standard machinery to replicate itself, until the cell explodes; sort of like a DNA/RNA injection exploit.
Life's two most fundamental properties are homeostasis and reproduction. The loss of these two combined with its parasitic nature makes this cell a form on non-life.
how do biologist consider virus like replication then ? which is a two-part system, the virus + the host (and even, a dense population of hosts)
Lots of types of life give up on homeostasis along particular dimensions because the environment is doing it well enough. Viruses do reproduce.
If you say "well not by themselves" neither do humans.
No life exists "by themselves". Self-replication means using only its own DNA and not mangling with other's. Virii are not only parasites but dead matter (a ribonucl molecule surrounded by proteins that happens to stick to other cells, like dirt on the skin). Gut microbioma is parasite.
There is another life property that this object does not fulfill and is called Teleonomia, that is governed by an ultimate goal.
> the bacterium Carsonella ruddii, which lives as a symbiont within the guts of sap-feeding insects, has an even smaller genome than Sukunaarchaeum, at around 159,000 base pairs
159 000 base pairs is ~320 Kbit, or 40 KBytes. I wonder, if that is the minimum size of a cell firmware. Also, if the cell is that simple, can we study it exhaustively and completely? Like, decipher every base pair in DNA, and determine what it is responsible for. And make an interactive website for that.
Makes me wonder, do geneticist count epigenetic methylation as information to add to the genetic information set ?
This is the biological equivalent of sectorlisp.
From the paper: https://www.biorxiv.org/content/10.1101/2025.05.02.651781v1
> ... we report the discovery of Candidatus Sukunaarchaeum mirabile, a novel archaeon with an unprecedentedly small genome of only 238 kbp —less than half the size of the smallest previously known archaeal genome— from a dinoflagellate-associated microbial community.
For comparison, the smallest bacteria genome, nasuia deltocephalinicola, is 139 kbp.
Hm. Not the biggest fan of the "parasite" framing given how little we know. I feel the default should be something more like lichens.
The standard definition of life is too restrictive.
I suggest
Or, in other words, things that can evolve.I find the idea that viruses aren't alive ridiculous.
Atoms and sub-atomic particles fit this definition.
Machines fit this definition.
Fire fits this definition.
Truth is "life" is not a distinct category. We just think of life as complex life. A complex system that mines energy gradients to preserve and replicate its forms.
But there's no hard boundary. It's just in our head.
How do any of those things fit that definition?
Code can fit the definition. Genetic algorithms.
Yep.
People always come up with people-centric definitions. They need to be updated based on what are the fundamental characteristic of something that is alive.
The current, more standard definition, seems to be based on metabolism. I disagree and argue for reproduction and evolution.
No, none of those can mutate, that's the point of "and mutate heritably"
Crystals can "reproduce", but it's always the same (there can be errors, but they don't inherit), so they don't count.
And atoms don't reproduce, so I'm missing your point there.
I think the genome might be mostly just the "config file". So the cell already contains most of the information and mechanisms needed for the organism. The genome is config flags and some more detailed settings that turn things on and off in the cell, at specific times in the life of the organism. From this point of view, the discussion about how many pairs/bytes of information are in the genome is misleading. Similar analogy: I can write a hello world program, which displays hello world on the screen. But the screen is 4k, the windows background is also visible, so the hardware and OS are 6-8 orders of magnitude more complex than the puny program, and the output is then much more complex than the puny program.
400K should be enough for any body
Maybe this is a case of an inception of overlapping genes?
I’ve been thinking about a wild theory regarding the incredible biological complexity we see in mammals today.
What if our bodies (apart from the brain) are actually the result of an ancient aggregation of once-separate "organisms" that evolved to live symbiotically?
Over millions of years, their DNA might have fused and co-evolved into a single, unified genome. What began as cooperation between distinct life forms could have gradually become inseparable, giving rise to the intricate multicellular systems we now take for granted.
It's called Symbiogenesis [0] and it's not at all a wild theory. But it's limited to cell components, not multiples organs fusing to create something as complex as a mammal.
[0] https://en.wikipedia.org/wiki/Symbiogenesis
Why do you say "apart from the brain"?
Also, as others have noted, your idea is not necessarily wild. Certainly, at the sub-cellular level, there is tremendous evidence that symbiosis played a part in creating "higher level" organisms (i.e., eukaryotes).
Many genomes are like a junk-yard with fossilized relics of infectious agent nucleic acid (e.g., viruses), etc. Apologies for the junk-yard / fossil mixed metaphor.
This isn't a wild theory or a novel one. It's well-established that endogenous retroviruses alter DNA and are inherited. In addition to the primary genome being modified this way, all mitochondria are symbiotic organisms inside plant and animal cells, with their own DNA, and are vital to life. Same thing for chloroplasts in plants. And then there are gut bacteria, which are vital to life, symbiotic, and directly influence evolution and the genome.
https://en.wikipedia.org/wiki/Intragenomic_conflict
You should look into the origin of mitochondria.
I believe that we’re living in that situation now. I don’t think life can be divided into smaller organisms. That there is just one complex life that we failed to see based on our past prejudice.
See also: “Microbe with bizarrely tiny genome may be evolving into a virus” – https://www.science.org/content/article/microbe-bizarrely-ti...
Which, BTW, is about the same researcher and microbial host/parasite pair. More info, so I'm not complaining.
Yeah, I should have mentioned that. Article about the same topic and preprint, but released earlier this year.
Maybe devolving would be a better term if that's the case
Impressive. However, still a-ways to go before its as degenerate as viruses like SARS-CoV-2 (which have an order of magnitude fewer base-pairs)
> According to the shocked researchers
What is this, some content creator run Biohacker Lab in some basement on Microflix premises?
Ominous voice: the tiny cell withdrew into the cracks of existence and saved it's entire code to be in the lines between, the Singular Point which was neither a fraction of space, nor a unit of time, hidden in the void of Chututululu's (33rd degree cousin of Cthulhu) dreams, written in the unspeakable language of the subtext of the book of neither life nor death, that nobody would decipher until the time was right AND GODZILLA GETS TO WALK THE EARTH AGAIN.
They were shocked. It is shocking.
Well tell them to quit playing with the stun gun.
This is cool but doesn't say much about the definition of life IMO. They're obligate parasites. This isn't a new category. They're still eating stuff from their host (probably, given the caveat later in the article), and still using it to replicate, it's just a more limited diet.
> They're still eating stuff from their host
They aren’t. Apart from DNA replication, transcription, and translation, their genome lacks elements encoding for even the most simple metabolic pathways.
Then where are they getting the materials to replicate? Where are they getting the energy? Magic? No, they're pulling pre-metabolized materials and energy from the host.
Talking about tiny cells and staring at a tube with liquid. Made me chuckle.
The ultimate form of outsourcing.
Which makes C. Regius a very tiny CEO? :)
Only if it has a mechanism to send signals into the host and cell. For the CEO metaphor to hold, I'll accept that these signals can be entirely ignored, but they need to be transmitted.
There must be some interaction with the host involved. Otherwise there is no point in being hosted or stripping off own features.
What do you mean? The interaction described in the article is just of the small cell stealing nutrients from the host's pouch. That seems like enough of a "point" for the parasitic cell, while giving it zero incentive to advertise its presence with signals.
Reminds me of how the discovery of giant viruses - like truly huge viral particles - was immediately also followed by discovering "virophages" which parasitized them.
Which of course makes sense to some degree: if an adaptive strategy is successful enough, then parasitizing something which successfully implements it is going to be resource favorable (and likely, presumably by being a member of that species and just shedding components you don't need if you take them).
Indeed. Well deduced.
Inevitability of Genetic Parasites Open Access Jaime Iranzo, Pere Puigbò, Alexander E. Lobkovsky, Yuri I. Wolf, Eugene V. Koonin https://academic.oup.com/gbe/article/8/9/2856/2236450
Unsurprisingly maybe, DPANN archaea can also host viruses: https://www.nature.com/articles/s41564-025-02149-7 (Paywalled, but there’s a preprint at https://www.biorxiv.org/content/10.1101/2025.02.15.638363v1)
We don’t even fundamentally understand physics yet. Certainly there is much to life that we don’t understand.
This is not so much about the understanding of life as it is about the definition of life.
I don’t think a precise definition of life is particularly important or of particular interest to most biologists. This thing is life in the sense that it’s definitely in scope of being studied by biologists (same is true for viruses, of course). And the reason it is speculated that it may be crucial to understanding life is mentioned in the article: “This organism might be a fascinating living fossil—an evolutionary waypoint that managed to hang on.”
Eh, you're quibbling with words. We're getting closer to the quantum (indivisible) definition of life, and that's understanding.
I don't think that they are. The term life, as it's currently defined, is not very useful. The reality is that there is a very colorful spectrum of microscopic biology and that a single bin of "alive" and "not alive" is like trying to paint the mona lisa with a single pixel.
This scishow video gives a good look at the tip of the iceberg.
https://youtu.be/FXqmzKwBB_w
As they said in another comment, life is the ability to decrease entropy. That definition would tie in quantum mechanics.
We understand enough physics to model all the possible interactions life might have on this planet. Unless this planet is having a really bad day.
Maybe better to say "We understand enough physics to model all the possible interactions PHYSICS might have on this planet".
There are many levels of abstraction between quantum/particle physics and life, or even just cosmology (things like dark matter, etc), that we really know very little about.
Let SCOTUS have a look, they seem to know what life is without the benefit of any bothersome science.
Virus are simpler and have challenged the definition of life for a long time already. This article excludes virus from life because they lack ribosomes.
Last time I checked, they are considered "not alive" when outside of a host, and "alive" when inside a host.
About size: "Genome size varies greatly between species. The smallest—the ssDNA circoviruses, family Circoviridae—code for only two proteins and have a genome size of only two kilobases;[61] the largest—the pandoraviruses—have genome sizes of around two megabases which code for about 2500 proteins"
https://en.wikipedia.org/wiki/Virus
The definition of life is also uninteresting. At its core it is just a vocabulary and classification issue. We humans invented the word life and we humans chose to make the word vague, confusing and differently defined among different people. An arbitrary vocabulary and definitional choice for a word “life” is not in actuality interesting to think about.
Yet people get hung up about it as if it’s a philosophical problem. It is not a philosophy problem. The word is loaded and you’re simply spending an inordinate amount of time trying to define some made up boundary of what fits this category you made up. It is a communication problem disguised as deeper.
It's like the word "planet", ultimately a tired game of definitions.
This sounds more like a SuperVirus than a cell to me ¯\_(ツ)_/¯
Can we also study very small collections of sand to challenge the definition of what counts as a heap?
Life is the process of decreasing entropy. If they stick with that definition, they’d be fine. And they’d find out that life is even more abundant than they can imagine.
This is one of those things that sounds profound, but only until you think about it. Depending on how you read this, it either excludes life entirely or includes all sorts of things that are not meaningfully alive.
1. Living things locally decrease entropy but globally increase it.
2. Many other processes do the same. As chermi noted, a liquid solidifying has the same characteristic.
I definitely choose the second of your two outcomes. That it includes all sorts of things that you think are not meaningfully alive. But these things are actually life.
Yes, living things locally decrease entropy and that’s my point.
And maybe I should’ve been more clear for people who cannot grasp new understandings, anything that can decrease its own entropy is living.
I mean, do you think life has nothing to do with the organization matter into a lower entropy state?
What? A liquid solidifying is life?
Water does not decrease its own entropy. If you can’t understand the distinction I’m making then you do not have the imagination and creativity to create new understanding.
A glass of water in a cold environment radiates away heat until it freezes, decreasing its local entropy and increasing global entropy.
> If you can’t understand the distinction I’m making then you do not have the imagination and creativity to create new understanding.
Perhaps you could explain your distinction instead of insulting people. It’s possible you have some interesting and insightful distinction but as of now you’ve not explained it nor given any examples of this “more abundant” life.
I’m not insulting you. I’m pointing out a reality. You’re reading comprehension is failing you right now.
Water does not freeze itself. That is the distinction. But myself, as a living being, can turn water into ice. And I can create an organize materials inside of my own body.
I pointed out something interesting. The least thing you could do is actually look up to see if there’s any validity or research on what I’m talking about.
By more abundant life, I’m talking about how the definition of life we have is limited, but it’s ever expanding based on the papers of the original post. I’m talking about a greater expansion of our understanding of life that’s discussed in papers that deal with entropy and life.
For instance:
https://www.quantamagazine.org/a-new-thermodynamics-theory-o...
But this has been a topic of conversation since the early 1900s. It’s not like I’m saying anything new.