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I read the article waiting for an answer to the question "in what operational sense does this matter?" but it never arrived. The question posed is whether we c

I read the article waiting for an answer to the question "in what operational sense does this matter?" but it never arrived. The question posed is whether we consider mitochondria to be "alive". It's just a word, who cares. What do we do differently given this assumption?

bmacho 2y ago
Ew. That's always an uncomfortable read.
pizzathyme 2y ago
Exactly. Seems similar to "are LLMs alive"? What practical purpose would an answer to that question serve?
- The_Colonel 2y ago
  That seems to be an overly reductive view on the value of knowledge. What practical purpose does studying ancient civilizations have? Why do we send expensive telescopes into space to study faraway galaxies and try to uncover mysteries of the big bang? When can we expect the results from number theory to lower the price of gas at the pump?
  - deleted 2y ago
    [deleted]
  - andrewla 2y ago
    But the definition of a word is not knowledge. Knowing that mitochondria have their own DNA is knowledge. Knowing that they reproduce independently of their home cell is knowledge. Learning whether they evolved from a separate viable organism would be knowledge. Learning whether we can make them viable, or breed them separately, and use them in therapies -- all knowledge. Whether they are "alive" or not is just the definition of a word.
    - dekhn 2y ago
      Much of science is about defining words in ways that match the underlying general structure of the system being studied. A subset of scientists want to come up with an operational definition of "What is life", which may or may not include things like viruses and mitochondria. As you say, it's mostly definitional, but by defining this, we can potentially make our understanding match up with the latent reality.
nemonemo 2y ago
It doesn't seem the article addresses this, but I'd ask these questions: "would it be possible that mitochondria's evolutional interest and the organism's interest are not aligned?" "how many independent DNA can an organism possess?" "why mitochondria do not elicit immune reactions? Or can they?"
- hammock 2y ago
  1) https://en.wikipedia.org/wiki/Mother%27s_curse https://en.wikipedia.org/wiki/Mother%27s_curse 2) By "organism" I assume you mean "cell" since humans have several thousand different species with their own DNA living on or inside the body at any given moment. We can speak of animal cells, which have two (species and mitochondria) - and plant cells, which have three (species, mitochondria, and chloroplasts). If there can be one two or three, I don't see why there couldn't be even more. 3) Mitochondria are usually sequestered within the cell, which limits their exposure to immune cells. The immune system primarily targets pathogens that are outside the host cells. In fact, some pathogens can exploit mitochondrial pathways to evade immune detection - the most famous of which is HIV.
  - nemonemo 2y ago
    Thank you for these amazing answers. Mother's curse is a notion I had no idea of, but it makes sense now that I think about it. And chloroplasts have separate DNAs from the species ones? That really is also eye-opening.. Biology is full of wonders.
davideg 2y ago
> Defining mitochondria as “nonliving” isn’t just a classification mistake, nor a question of word choice. Rather, it is a fundamental misunderstanding of the nature and role of mitochondria. It inherently undermines our understanding of biological systems and deeply influences the tools we build to study them. Once you accept mitochondria as alive, you might be motivated to explore its "potential" niche, as described by the author. The example of implanting cross-species mitochondria in human cells (e.g. from a gorilla) might lead to novel therapies. It's about breaking outside the box of mitochondria having to live inside specific environments.
- andrewla 2y ago
  So the theory is that if we don't accept them as alive, then we can't experiment with implanting cross-species mitochondria in human cells? Why not? What stops us from doing this?
  - davideg 2y ago
    This is a fair point. I can see the excitement around recognizing that mitochondria is alive to motivate exploring its other functions. But I think you're right someone might be interested in that exploration regardless of whether it's considered alive. Edit: to your point, there are plenty of scientists interested in studying viruses and much debate about whether or not they are alive. Ultimately it probably doesn't matter. I do think when you consider mitochondria to be alive, it broadens the scope of your thinking because you start considering each characteristic of life in relation to mitochondria. You might not be motivated to do that without thinking in those terms.
- davideg 2y ago
  I recognize that you might be motivated to explore removing and implanting mitochondria regardless of whether you consider it to be alive (as you might think about implanting an organ from another source). I think the main point the author is making is to not fall prey to reductive thinking about mitochondria's potential and less about the question of "aliveness". We were all taught about mitochondria producing ATP, but it sounds like it serves many other functions and there's a lot more to explore about its potential in synthetic biology and therapeutics.
dekhn 2y ago
It matters for a number of reasons, but the main reason in terms of pure biology is that it was not originally recognized that cells could absorb other cells and utilize them for the absorbed cell's natural function. This meant, importantly, that we learned cells did not always need to evolve a functionality from scratch, but could acquire it through phagocytosis. It's also a useful tool for studying evolution for many reasons.
- andrewla 2y ago
  Whether or not mitochondria were once viable independent organisms that were absorbed by early eukaryotes does not depend on whether we call their modern descendants "living" or not. If we determine that they did, then we still don't have to call them alive -- certainly things like mitosomes exist and are suspected to have either evolved from mitochondria or evolved after amitochondrial division, but do not have DNA and do not reproduce independently but fulfil similar functions. We know they have DNA, we know they reproduce independently of the host cell, we know to a degree why they tend to move to both sides on cell division. We know lots of stuff about them and we can always learn lots more. Whether they are "alive" or not has absolutely no bearing on that, other than to naval-gaze.
  - dekhn 2y ago
    Oh, I see, you're getting hung up on the use of the term alive for modern mitochondria. This sort of definitional argument is not interesting to me.
    - andrewla 2y ago
      I think we're in agreement then -- this article is not about "did mitochondria evolve from absorbed viable organisms as opposed to evolving directly", which is an interesting question that impacts our understanding of evolution in microbiology. The article is about whether "Microchondria Are Alive" which is a useless naval-gaze.
      - dekhn 2y ago
ASalazarMX 2y ago
I was equally dismissive of the actual importance of philosophizing whether mitochondrias are alive or not, but this paragraph made me change my mind. > It seems Mitochondria are not bound to their host cell; they can travel between different cells. Although different species carry distinct mitochondria, experiments show that mitochondria from one species can be transferred to another. > In 1997, scientists isolated mitochondria from chimpanzees and gorillas and showed that they are naturally internalized and integrated into human cells. Notably, the addition of external mitochondria even showed therapeutic benefits in heart failure and spinal cord injury. Thus, the potential niche that mitochondria can live in is greater than their effective niche. So it seems like they are more symbiote than organelle, that's amazing.
Symmetry 2y ago
The question itself if just semantics. But considering our mitochondria as evolving populations subject to selective pressure and genetic drift is really important to understanding their role in our health, down to basic questions like "Why is exercise healthy?"

bmacho 2y ago

Ew. That's always an uncomfortable read.

pizzathyme 2y ago

Exactly. Seems similar to "are LLMs alive"? What practical purpose would an answer to that question serve?

The_Colonel 2y ago
That seems to be an overly reductive view on the value of knowledge. What practical purpose does studying ancient civilizations have? Why do we send expensive telescopes into space to study faraway galaxies and try to uncover mysteries of the big bang? When can we expect the results from number theory to lower the price of gas at the pump?
- deleted 2y ago
  [deleted]
- andrewla 2y ago
  But the definition of a word is not knowledge. Knowing that mitochondria have their own DNA is knowledge. Knowing that they reproduce independently of their home cell is knowledge. Learning whether they evolved from a separate viable organism would be knowledge. Learning whether we can make them viable, or breed them separately, and use them in therapies -- all knowledge. Whether they are "alive" or not is just the definition of a word.
  - dekhn 2y ago
    Much of science is about defining words in ways that match the underlying general structure of the system being studied. A subset of scientists want to come up with an operational definition of "What is life", which may or may not include things like viruses and mitochondria. As you say, it's mostly definitional, but by defining this, we can potentially make our understanding match up with the latent reality.

nemonemo 2y ago

It doesn't seem the article addresses this, but I'd ask these questions: "would it be possible that mitochondria's evolutional interest and the organism's interest are not aligned?" "how many independent DNA can an organism possess?" "why mitochondria do not elicit immune reactions? Or can they?"

hammock 2y ago
1) https://en.wikipedia.org/wiki/Mother%27s_curse https://en.wikipedia.org/wiki/Mother%27s_curse 2) By "organism" I assume you mean "cell" since humans have several thousand different species with their own DNA living on or inside the body at any given moment. We can speak of animal cells, which have two (species and mitochondria) - and plant cells, which have three (species, mitochondria, and chloroplasts). If there can be one two or three, I don't see why there couldn't be even more. 3) Mitochondria are usually sequestered within the cell, which limits their exposure to immune cells. The immune system primarily targets pathogens that are outside the host cells. In fact, some pathogens can exploit mitochondrial pathways to evade immune detection - the most famous of which is HIV.
- nemonemo 2y ago
  Thank you for these amazing answers. Mother's curse is a notion I had no idea of, but it makes sense now that I think about it. And chloroplasts have separate DNAs from the species ones? That really is also eye-opening.. Biology is full of wonders.

davideg 2y ago

> Defining mitochondria as “nonliving” isn’t just a classification mistake, nor a question of word choice. Rather, it is a fundamental misunderstanding of the nature and role of mitochondria. It inherently undermines our understanding of biological systems and deeply influences the tools we build to study them. Once you accept mitochondria as alive, you might be motivated to explore its "potential" niche, as described by the author. The example of implanting cross-species mitochondria in human cells (e.g. from a gorilla) might lead to novel therapies. It's about breaking outside the box of mitochondria having to live inside specific environments.

andrewla 2y ago
So the theory is that if we don't accept them as alive, then we can't experiment with implanting cross-species mitochondria in human cells? Why not? What stops us from doing this?
- davideg 2y ago
  This is a fair point. I can see the excitement around recognizing that mitochondria is alive to motivate exploring its other functions. But I think you're right someone might be interested in that exploration regardless of whether it's considered alive. Edit: to your point, there are plenty of scientists interested in studying viruses and much debate about whether or not they are alive. Ultimately it probably doesn't matter. I do think when you consider mitochondria to be alive, it broadens the scope of your thinking because you start considering each characteristic of life in relation to mitochondria. You might not be motivated to do that without thinking in those terms.
davideg 2y ago
I recognize that you might be motivated to explore removing and implanting mitochondria regardless of whether you consider it to be alive (as you might think about implanting an organ from another source). I think the main point the author is making is to not fall prey to reductive thinking about mitochondria's potential and less about the question of "aliveness". We were all taught about mitochondria producing ATP, but it sounds like it serves many other functions and there's a lot more to explore about its potential in synthetic biology and therapeutics.

dekhn 2y ago

It matters for a number of reasons, but the main reason in terms of pure biology is that it was not originally recognized that cells could absorb other cells and utilize them for the absorbed cell's natural function. This meant, importantly, that we learned cells did not always need to evolve a functionality from scratch, but could acquire it through phagocytosis. It's also a useful tool for studying evolution for many reasons.

andrewla 2y ago
Whether or not mitochondria were once viable independent organisms that were absorbed by early eukaryotes does not depend on whether we call their modern descendants "living" or not. If we determine that they did, then we still don't have to call them alive -- certainly things like mitosomes exist and are suspected to have either evolved from mitochondria or evolved after amitochondrial division, but do not have DNA and do not reproduce independently but fulfil similar functions. We know they have DNA, we know they reproduce independently of the host cell, we know to a degree why they tend to move to both sides on cell division. We know lots of stuff about them and we can always learn lots more. Whether they are "alive" or not has absolutely no bearing on that, other than to naval-gaze.
- dekhn 2y ago
  Oh, I see, you're getting hung up on the use of the term alive for modern mitochondria. This sort of definitional argument is not interesting to me.
  - andrewla 2y ago
    I think we're in agreement then -- this article is not about "did mitochondria evolve from absorbed viable organisms as opposed to evolving directly", which is an interesting question that impacts our understanding of evolution in microbiology. The article is about whether "Microchondria Are Alive" which is a useless naval-gaze.
    - dekhn 2y ago

ASalazarMX 2y ago

I was equally dismissive of the actual importance of philosophizing whether mitochondrias are alive or not, but this paragraph made me change my mind. > It seems Mitochondria are not bound to their host cell; they can travel between different cells. Although different species carry distinct mitochondria, experiments show that mitochondria from one species can be transferred to another. > In 1997, scientists isolated mitochondria from chimpanzees and gorillas and showed that they are naturally internalized and integrated into human cells. Notably, the addition of external mitochondria even showed therapeutic benefits in heart failure and spinal cord injury. Thus, the potential niche that mitochondria can live in is greater than their effective niche. So it seems like they are more symbiote than organelle, that's amazing.

Symmetry 2y ago

The question itself if just semantics. But considering our mitochondria as evolving populations subject to selective pressure and genetic drift is really important to understanding their role in our health, down to basic questions like "Why is exercise healthy?"