Book review - Power, Sex, Suicide: Mitochondria and the meaning of life

Many works try to take a weirdly shaped lens through which to rechart a small portion of our map of the world. Power, Sex, Suicide does that through the lens of, ahem, mitochondria. The weirdest thing about it is how splendidly it succeeds.

I - What is this book about?

Almost 2 years after originally reading it, this beautiful aberration has remained ingrained in my brain in ways that surprise me.

This book is many things, among them, it's a reply to Andy Matuschak's and others that don't believe in a book's power to teach you technical topics.

Nick Lane somehow managed to pack an introduction into mitochondrial science together with an overview of the most fundamental questions of biology and a fair dose of storytelling and experiment-describing into a dry coat of British humor.

How did life originate? Why do we die? Why do we have sex and sexes? Why do we eat? How do we differentiate into species? How do paradigms and theories in the field of biology shift? How does evolution work? What causes cancer? How did the immune system evolve ?

Are among the questions addressed by this book. They are all questions I had decent answers to. But somehow this book managed to make them all seem new, gave it's own somewhat odd but seemingly very correct answer, and left my brain with a slight but observable perspective tilt in all of those areas.

It's hard to think of a person this book is aimed at specifically. It seems too technical for a lay audience and explains too many basic concepts to be aimed at people working in biochemistry, molecular bio, or cell bio. Yet it's hard for me to think of a single intelligent person to which I wouldn't recommend it.

II - What is this book actually about?

This book is about mitochondria, about trying to give a detailed and awe-invoking picture of this organism-organelle that's so foundational to eukaryote life.

It outlines theories about the bacterial progenitors of mitochondria and how the original symbiosis might have come about. From there it outlines things such as whether or not it happened multiple times and how in the world it could have happened only once.

It contains an engaging historical telling of how scientists discovered biological energy creation, it explains how mitochondria function, how previous generations thought they did, and how future generations might correct our misconceptions.

It grapples with why mitochondria exist in the first place, why they seem to be so crucial to tissue-differentiate organisms, why their genetic material ought to be preserved independently from that of the cell.

It does this in such a holistic way that it brings tears to my eyes. Presenting both the theoretical and experimental reasoning chains and trying to be so even-handed with each hypothesis that it feels hard to know the author's favorite, even though he outright tells you which one it is.

It spends 12 pages to reach a short "correct" statement like:

The speed of respiration is very sensitive to changing circumstances—whether we’re awake or asleep, or doing aerobics, sitting around, writing books, or chasing a ball. These sudden shifts demand that mitochondria adapt their activity at a molecular level—a requirement that is too important, and abruptly swinging, to be controlled at a distance by the bureaucratic confederation of genes far away in the nucleus.

But the core of this book is not formed of correct statements, but rather in the impressively large and well-argued inquiry chains, the author uses to write them.

I remember that Scott's review of The Structure Of Scientific Revolutions laments:

one of my big complaints about this book is that, for a purported description of How Science Everywhere Is Always Practiced, it really just gives five examples

This book contains at least 4 examples that could easily amend Khun's work and map it to biology. I found the most engaging one to be the foray into how eukaryotes produce energy.

It's a slowly progressing dance between current knowledge, available assays, and the theories resulting from the two. In nearly 50 pages the author goes from a picture of energy creation focused around the idea of fermentation, inspired by wine-making, to our modern conception of mitochondria with their fancy membrane including the 4 types of respiratory complexes chartering through various compounds to maintain the delicate balance involved in not killing our cells due to lack of ATP, while also not killing our cells due to overwhelming them with ROS or depleting them of NAD+.

Even though the book is about mitochondria, how they work and how we can view the world once we understand that, it's just as much a book about the living-breathing scientific method as it was applied throughout the ages

III - But now, really, what is this book actually about?

Ok, this book is probably not actually about the evolution of science. The author uses the "ask a question, look at the progress of answers through history" approach, but I think many books do that.

This book is about the origination of eukaryote life. After 70 pages of prefaces and introductions, the author's ponderings around the origination of eukaryotes open the first real chapter:

The void between bacterial and eukaryotic cells is greater

than any other in biology. Even if we begrudgingly accept bacterial colonies as true multicellular organisms, they never got beyond a very basic level of organization. This is hardly for lack of time or opportunity—bacteria dominated the world for two billion years, have colonized all thinkable environments and more than a few unthinkable ones, and in terms of biomass still outweigh all multicellular life put together. Yet for some reason, bacteria never evolved into the kind of multicellular organism that a man on the street might recognize. In contrast, the eukaryotic cell appeared much later (according to the main- stream view) and in the space of just a few hundred million years—a fraction of the time available to bacteria—gave rise to the great fountain of life we see all around us.

Solutions are suggested, though not always clearly delimited, sometimes it feels like speculation is just being thrown at the wall and blending into each other to form what could be the basis of hundreds of slightly different valid hypotheses.

We are presented with Nick Lane's favorite theory on the subject, the Hydrogen hypothesis, but after reading the chapter about it twice it still feels like a mess cobbled out of the part of different theories and observation rather than a coherent whole. This makes me hopeful that Nick Lane is actually presenting the ideas as they are rather than taking a popsciy hat and trying to do the whole "Unification of the field via glancing over every single interesting question using a metaphor or disclaimer".

The hydrogen hypothesis can be summed up as:

While methanogens are uniquely resourceful in their metabolic powers, they nonetheless face a serious obstacle... . The trouble is that, while carbon dioxide is plentiful, hydrogen is hard to come by in any environment containing oxygen, as hydrogen and oxygen react together to form water. From the point of view of a methanogen, then, anything that provides a little hydrogen is a blessing.

Hydrogenosomes are a double boon, because they release both hydrogen gas and carbon dioxide, the very substances that methanogens crave, in the process of generating their own energy. Even more importantly, they don’t need oxygen to do this—quite the contrary, they prefer to avoid oxygen—and so they function in the very low-oxygen conditions required by methanogens. No wonder the methanogens suckle up to hydrogenosomes like greedy piglets! The insight of Martin and Müller was to appreciate that this kind of intimate metabolic union might have been the basis of the original eukaryotic merger.

However, the books don't leave it at that and pick up the thread all the way to complex eukaryotic lifeforms. In the process, some interesting theories that don't seem related to mitochondria are approached. The one that stuck with me is how our immune systems may well have developed from the processes bacteria used to signal others in their colony when they wanted to get some DNA transferred to them. Since this usually happened when a bacteria was under some form of inter-cellular stress. This signal persisted in eukaryotes to form the basis of the much more complex interactions between cells and our immune system. How mitochondria are involved in all of this I leave to the reader to discover, however, as, with everything in these books, this thread of ideas does get tied back into them.

IV - So, is that all?

I keep feeling like I'm doing a disservice to the book by presenting its ideas here because I wouldn't want to tie it's content to just those few points. This is a work to be enjoyed one chapter at a time, you could probably go in mid-way through and you'd still enjoy it, you could pause in the middle and read the rest 1 year later, and you'd be right back on track. So honestly, I can only describe bits of certain chapters, because to describe the whole would be to rewrite the whole book.

There is one thing though, which this book made me realized, which only clicks when it's read as an individual unity. Which is a glimpse into the thought process of a specialist in a field.

I don't mean a glimpse into his knowledge of his particular field, but rather a glimpse into how he integrates "the rest of science" in a mindset where it becomes subservient to his niche interested, in a way that enhances it, that gives the rest of us a new perspective on that "rest of science".

Even more so, this is done in a very respectful and, ahem, scientific? manner. In that, the author is never cherry-picking suitable evidence from other fields. More so, he seems to be doing in-depth dives and bringing in both the things that confirm his views and those that threaten them. Indeed, to the author's credit, I'm not even sure what his personal views are on many of the contested subjects approached by the book, I might even go as far as to compliment him in stating that he has none.

What he does have, however, is a strong fascination with creating edges in the graph of human knowledge between mitochondria, energy production, eukaryote evolution, and everything else. At least that is the feeling I get from reading the book. I find this kind of healthy obsession to be rare and fascinating, very enjoyable to observe, and to voyeuristically partake in for a few hours.

In my library of pop-biology, this book stands in a place of honor, next to Sapolsky's course in human behavioral biology and The Selfish Gene. I can't help but recommend it.

Published on: 2020-10-24



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