How to afford a big sloppy genome

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My direct experience with prokaryotes is sadly limited — while our entire lives and environment are profoundly shaped by the activity of bacteria, we rarely actually see the little guys. The closest I've come was some years ago, when I was doing work on grasshopper embryos, and sterile technique was a pressing concern. The work was done under a hood that we regularly hosed down with 95% alcohol, we'd extract embryos from their eggs, and we'd keep them alive for hours to days in tissue culture medium — a rich soup of nutrients that was also a ripe environment for bacterial growth. I was looking at the development of neurons, so I'd put the embryo under a high-powered lens of a microscope equipped with differential interference contrast optics, and the sheet of grasshopper neurons would look like a giant's causeway, a field of tightly packed rounded boulders. I was watching processes emerging and growing from the cells, so I needed good crisp optics and a specimen that would thrive healthily for a good long period of time.

It was a bad sign when bacteria would begin to grow in the embryo. They were visible like grains of rice among the ripe watermelons of the cells I was interested in, and when I spotted them I knew my viewing time was limited: they didn't obscure much directly, but soon enough the medium would be getting cloudy and worse, grasshopper hemocytes (their immune cells) would emerge and do their amoeboid oozing all over the field, engulfing the nasty bacteria but also obscuring my view.

What was striking, though, was the disparity in size. Prokaryotic bacteria are tiny, so small they nestled in the little nooks between the hopper cells; it was like the opening to Star Wars, with the tiny little rebel corvette dwarfed by the massive eukaryotic embryonic cells that loomed vastly in the microscope, like the imperial star destroyer that just kept coming and totally overbearing the smaller targets. And the totality of the embryo itself — that's no moon. It's a multicellular organism.

I had to wonder: why have eukaryotes grown so large relative to their prokaryotic cousins, and why haven't any prokaryotes followed the strategy of multicellularity to build even bigger assemblages? There is a pat answer, of course: it's because prokaryotes already have the most successful evolutionary strategy of them all and are busily being the best microorganisms they can be. Evolving into a worm would be a step down for them.

That answer doesn't work, though. Prokaryotes are the most numerous, most diverse, most widely successful organisms on the planet: in all those teeming swarms and multitudinous opportunities, none have exploited this path? I can understand that they'd be rare, but nonexistent? The only big multicellular organisms are all eukaryotic? Why?

Another issue is that it's not as if eukaryotes carry around fundamentally different processes: every key innovation that allowed multicellularity to occur was first pioneered in prokaryotes. Cell signaling? Prokaryotes have it. Gene regulation? Prokaryotes have that covered. Functional partitioning of specialized regions of the cell? Common in prokaryotes. Introns, exons, endocytosis, cytoskeletons…yep, prokaryotes had it first, eukaryotes have simply elaborated upon them. It's like finding a remote tribe that has mastered all the individual skills of carpentry — nails and hammers, screws and screwdrivers, saws and lumber — as well as plumbing and electricity, but no one has ever managed to bring all the skills together to build a house.

Nick Lane and William Martin have a hypothesis, and it's an interesting one that I hadn't considered before: it's the horsepower. Eukaryotes have a key innovation that permits the expansion of genome complexity, and it's the mitochondrion. Without that big powerplant, and most importantly, a dedicated control mechanism, prokaryotes can't afford to become more complex, so they've instead evolved to dominate the small, fast, efficient niche, leaving the eukaryotes to occupy the grandly inefficient, elaborate sloppy niche.

Lane and Martin make their case with numbers. What is the energy budget for cells? Somewhat surprisingly, even during periods of rapid growth, bacteria sink only about 20% of their metabolic activity into DNA replication; the costly process is protein synthesis, which eats up about 75% of the energy budget. It's not so much having a lot of genes in the genome that is expensive, it's translating those genes into useful protein products that costs. And if a bacterium with 4400 genes is spending that much making them work, it doesn't have a lot of latitude to expand the number of genes — double them and the cell goes bankrupt. Yet eukaryotic cells can have ten times that number of genes.

Another way to look at it is to calculate the metabolic output of the typical cell. A culture of bacteria may have a mean metabolic rate of 0.2 watts/gram; each cell is tiny, with a mass of 2.6 x 10-12g, which means each cell is producing about 0.5 picowatts. A eukaryotic protist has about the same power output per unit weight, 0.06 watts/gram, but each cell is so much larger, about 40,000 x 10-12g, that a single cell has about 2300 picowatts available to it. So, more energy!

Now the question is how that relates to genome size. If the prokaryote has a genome that's about 6 megabases long, that means it has about 0.08 picowatts/megabase to spare. If the eukaryote genome is 3,000 megabytes long, that translates into about 0.8 picowatts of power per megabase (that's a tenfold increase, but keep in mind that there is wide variation in size in both prokaryotes and eukaryotes, so the ranges overlap and we can't actually consider this a significant difference — they're in the same ballpark).

Now you should be thinking…this is just a consequence of scaling. Eukaryotic power production per gram isn't any better than what prokaryotes do, all they've done is made their cells bigger, and there's nothing to stop prokaryotes from growing large and doing the same thing. In fact, they do: the largest known bacterium, Thiomargarita, can reach a diameter of a half-millimeter. It gets more metabolic power in a similar way to how eukaryotes do it: we eukaryotes carry a population of mitochondria with convoluted membranes and a dedicated strand of DNA, all to produce energy, and the larger the cell, the more mitochondria are present. Thiomargarita doesn't have mitochondria, but it instead duplicates its own genome many times over, with 6,000-17,000 nucleoids distributed around the cell, each regulating its own patch of energy-producing membrane. It's functionally equivalent to the eukaryotic mitochondrial array then, right?

Wrong. There's a catch. Mitochondria have grossly stripped down genomes, carrying just a small cluster of genes essential for ATP production. One hypothesis for why this mitochondrial genome is maintained is that it acts as a local control module, rapidly responding to changes in the local membrane to regulate the structure. In Thiomargarita, in order to get this fine-tuned local control, the whole genome is replicated, dragging along all the baggage, and metabolic expense, of all of those non-metabolic genes.

Because it is amplifying the entire genomic package instead of just an essential metabolic subset, Thiomargarita's energy output per gene plummets in comparison. That difference is highlighted in this illustration which compares an 'average' prokaryote, Escherichia, to a giant prokaryote, Thiomargarita, to an 'average' eukaryotic protist, Euglena.

cellpower.jpeg
(Click for larger image)

The cellular power struggle. a-c, Schematic representations of a medium sized prokaryote (Escherichia), a very large prokaryote (Thiomargarita), and a medium-sized eukaryote (Euglena). Bioenergetic membranes across which chemiosmotic potential is generated and harnessed are drawn in red and indicated with a black arrow; DNA is indicated in blue. In c, the mitochondrion is enlarged in the inset, mitochondrial DNA and nuclear DNA are indicated with open arrows. d-f, Power production of the cells shown in relation to fresh weight (d), per haploid gene (e) and per haploid genome (power per haploid gene times haploid gene number) (f). Note that the presence or absence of a nuclear membrane in eukaryotes, although arguably a consequence of mitochondrial origin70, has no impact on energetics, but that the energy per gene provided by mitochondria underpins the origin of the genomic complexity required to evolve such eukaryote-specific traits.

Notice that the prokaryotes are at no disadvantage in terms of raw power output; eukaryotes have not evolved bigger, better engines. Where they differ greatly is in the amount of power produced per gene or per genome. Eukaryotes are profligate in pouring energy into their genomes, which is how they can afford to be so disgracefully inefficient, with numerous genes with only subtle differences between them, and with large quantities of junk DNA (which is also not so costly anyway; remember, the bulk of the expense is in translating, not replicating, the genome, and junk DNA is mostly untranscribed).

So, what Lane and Martin argue is that the segregation of energy production into functional modules with an independent and minimal genetic control mechanism, mitochondria with mitochondrial DNA, was the essential precursor to the evolution of multicellular complexity — it's what gave the cell the energy surplus to expand the genome and explore large-scale innovation.

As they explain it…

Our considerations reveal why the exploration of protein sequence space en route to eukaryotic complexity required mitochondria. Without mitochondria, prokaryotes—even giant polyploids—cannot pay the energetic price of complexity; the lack of true intermediates in the prokaryote-to-eukaryote transition has a bioenergetic cause. The conversion from endosymbiont to mitochondrion provided a freely expandable surface area of internal bioenergetic membranes, serviced by thousands of tiny specialized genomes that permitted their host to evolve, explore and express massive numbers of new proteins in combinations and at levels energetically unattainable for its prokaryotic contemporaries. If evolution works like a tinkerer, evolution with mitochondria works like a corps of engineers.

That last word is unfortunate, because they really aren't saying that mitochondria engineer evolutionary change at all. What they are is permissive: they generate the extra energy that allows the nuclear genome the luxury of exploring a wider space of complexity and possible solutions to novel problems. Prokaryotes are all about efficiency and refinement, while eukaryotes are all about flamboyant experimentation by chance, not design.


Lane N, Martin W. (2010) The energetics of genome complexity. Nature 467(7318):929-34.

31 Comments

Unfortunately I didn’t understand any of this, but I attribute that to the sauzamargaritas I was drinking.

Every time someone says they don’t understand something I wrote, I cry a little deep down inside. Why do you hate me so?

Ah, it’s esoteric, but not that bad. I’m not a biologist but I could half-follow it. I’ll come back later and pick up the other half.

Cheer up, PZ. I understood the gist of it. Your science writing is terrific - you help the reader follow the more technical details.

PZ Myers said:

Every time someone says they don’t understand something I wrote, I cry a little deep down inside. Why do you hate me so?

Then it must be positively awful to think of all the lurkers that read it, don’t understand any of it, and say nothing!

If it makes you feel better, I think I understood it. Though I’ll have to chew on it for awhile to really appreciate it.

There are some physics perspectives that fall into the “consider a spherical cow” category of explanations.

Whenever a condensed matter system grows in complexity, any energy-driven organization and coordination emerges within that system depends not only on the influx of energy through the surface of the system, but the flow of energy into the interior of the system as well as any outflow necessary to maintain a flux of energy (and matter) within the interior.

And it is the flow of energy that maintains any coordination and organization. If there are large differences within the system (diffusive and conductive pathways are heavily dependent on structure and coupling among the constituent parts of the system) then one would expect to see completely different processes capable of being sustained in different parts of such a system, and the system begins to look more like a composite system.

Now that’s ok provided that such differences contribute to an over all system that survives selection within a larger environment. And that is the cool thing about this because whatever falls out has not been planned ahead; it is just one of the composite systems that keep functioning in the given environment.

So we can almost begin to see the bridge between abiogenesis and living systems sorted by natural selection.

Interesting idea. Thanks for the summary. I also enjoyed your “fisking” of Oklahoma’s latest elected moron, Mr. Breechen. I have been pounding on him in his hometown newspaper.

Ironoically, it is called the The Durant Daily Democrat.

I’m not even a biologist but I understood the whole thing!

Bacteria are like rice, right?

(Sort of puts me off my sushi, I must say.)

…made sense to me (but a megabyte has stolen into your megabases)

Gary Hurd said:

Interesting idea. Thanks for the summary. I also enjoyed your “fisking” of Oklahoma’s latest elected moron, Mr. Breechen. I have been pounding on him in his hometown newspaper.

Ironoically, it is called the The Durant Daily Democrat.

And a great pounding it is; bravo!

bigjohn756 said:

Unfortunately I didn’t understand any of this, but I attribute that to the sauzamargaritas I was drinking.

Well Big John, if I understood it correctly:

Imagine if every electronic gadget you owned was an exact copy of your full-sized PC. You use one of these extra computers to watch TV shows, another one to tell the time, one just to make phone calls, and another add up your receipts. Meanwhile your neighbor only owns a single PC but also has a TV, a wristwatch, a landline phone, and a pocket calculator.

You both have at least one computer (normal genome). But those specialized, power-sipping gadgets your neighbor has are like the mitochondria, whereas your duplicate PCs are your full-genome copies being shoehorned into the same tasks. A landline phone is much more efficient for the task of calling someone up to talk about your in-laws than a great big computer is. Mitochondria are much more efficient at making sure a cell has enough energy than having many copies of the cell’s genome would be.
Hope that’s clear enough to be heard in Margaritaville.

I have been pounding on him in his hometown newspaper.

I just read that article by Bleached-brain.

holy.

crap.

I can’t recall seeing anything quite that stupid coming out of the mouth of an actual elected senator before.

I’ve seen similar, incoherent, garbage coming from the mouths of 12 year old creationists (and I can provide the link)!

jaw droppingly inane.

Glad you did such a thorough job there, but sweet plastic bobbleheaded JESUS!!

that guy will probably only understand about 10% of the words you wrote, let alone the content, even IF he reads it.

wow.

That guy makes IBIGGY look SMART!

Hey! Leave PZ alone - he’s blogging science for a change and he needs to be encouraged in that!

Chris Caprette said:

Then it must be positively awful to think of all the lurkers that read it, don’t understand any of it, and say nothing!

Not to mention the lurkers that read it, don’t understand any of it, but comment anyway, pretending that they do understand…

PS: If you of you guys happens to be “knethrea” you should really chill with the ““Holy Book” of Stupid” which only alienates Christians like “scrappymom” who would otherwise be an ally.

Ichthyic said:

wow.

I’ve got to the point where it is VERY hard to read creotroll arguments like the senator’s – they just repel me, if it was from someone just talking to the phone on me, I would hang up on them in mid-sentence.

There’s a certain vague fear that, whatever they have, it’s contagious. “The stupid, it burns!” Well, minor thanks that he’s just a state senator.

Well, minor thanks that he’s just a state senator.

Yeah. But, he is only 30 years old.

Gary Hurd said:

Well, minor thanks that he’s just a state senator.

Yeah. But, he is only 30 years old.

Yeah, he could be the next Jesse Helms.

Dale Husband said: Yeah, he could be the next Jesse Helms.

Think bigger: Nehemiah Scudder.

On the subject of multicellularity…

Nucleated human cells tend to have diameters of between 10 and 100 microns. The range of sizes of metazoan cells is greater. Bacteria that live in the human body have various shspes, but cocci tend to be be around 2 microns in diameter, and except for some smaller obligate intracellular pathogens, they’re all in the same ballpark. Infection causing free living amoebae are eukaryotes and are in the same size range as human cells.

Being mainly familiar with human cells and pathogens, I tend to think that there is a “size gap” between eukaryotic, or at least metazoan, cells and prokaryotic cells. The typical “pond water” unicellular harmless eukaryotic microbes tend to be in that range, too.

However, in fact, a fair number of eukaryotic single celled algae are in the 2-3 micron diameter range.

As far as I know, though, there are no multicellular organisms that are composed of very small individual cells. Being a eukaryote may not be as strongly associated with “large” cells as I once mistakenly thought, but multicellularity seems to be.

Nick Lane has written three popular science books, all highly recommended. His most recent Life Ascending identifies the ten biggest evolutionary innovations. Along the way, he includes a less technical explanation of the Lane-Wilson hypothesis, so for those who found PZ’s description too hard to follow, Lane himself is probably more accessible.

Shorter summary: just read his three books.

Fine commentary on the Lane/Martin hypothesis, PZ … and thanks too for the link to the Brecheen articles. It does illustrate the pitfalls of Tortucans elected to public office, doesn’t it?

Besides Valentine’s fine book on the phyla origin issue, I might toss in the case Conway Morris & Caron (2007) Science 315:1255-1258 make for linking up no less than three phyla with one common early Cambrian ancestor. Like all secondary citation addicts, though, Brecheen is unlikely to venture into reading primary work even when prodded.

I’m a lurker on this blog, an electronics engineer with a late-in-life-to-awaken fascination for evolutionary biology. Very happy to see Nick Lane’s books cited here. I’ve gobbled up most of the popular science books on evolution in recent years, and Lane is hands-down my favorite author.

PZ Myers does an excellent job of summarizing Lane’s idea here. I’d be interested to read others’ opinions of Lane’s musings on the origin of life from deep sea vents. The biochemistry, the geology, etc. Do his ideas hold water?

Eric Means said: I’m a lurker on this blog, an electronics engineer with a late-in-life-to-awaken fascination for evolutionary biology.

Another Sparky, huh? “It’s smoke that makes those things work – let the smoke out, they don’t work any more.”

Lane and Martin make their case with numbers. What is the energy budget for cells? Somewhat surprisingly, even during periods of rapid growth, bacteria sink only about 20% of their metabolic activity into DNA replication; the costly process is protein synthesis, which eats up about 75% of the energy budget. It’s not so much having a lot of genes in the genome that is expensive, it’s translating those genes into useful protein products that costs. And if a bacterium with 4400 genes is spending that much making them work, it doesn’t have a lot of latitude to expand the number of genes — double them and the cell goes bankrupt. Yet eukaryotic cells can have ten times that number of genes.

I think we are getting ahead of ourselves here. If you have a mutation that increases the size of the genome it increases the percentage of the energy budget that’s devoted to replication rather than protein synthesis. If you have a small energy budget that percentage is much larger than if you have a large energy budget. If you have a low energy environment you have negative selection against a larger genome but if you have a large energy environment it’s largely neutral. The 75/20 split is the result after negative selection because cells that do more protein synthesis win.

If what you are saying is true then there would be only differences between prokaryotes and eukaryotes in coding DNA but there is also a difference in non-coding DNA. We can see the transition from negative to neutral selection for genome size in the lack of any pattern in genome size either for coding or non-coding DNA in eukaryotes.

I saw this because I do low power design. What we do is we take less essential portions of the design that may already be contributing a small portion of the power budget and starve them more. You cannot take the absolute percentages and infer what the effects of low energy are.

Lane and Martin make their case with numbers. What is the energy budget for cells? Somewhat surprisingly, even during periods of rapid growth, bacteria sink only about 20% of their metabolic activity into DNA replication; the costly process is protein synthesis, which eats up about 75% of the energy budget. It’s not so much having a lot of genes in the genome that is expensive, it’s translating those genes into useful protein products that costs. And if a bacterium with 4400 genes is spending that much making them work, it doesn’t have a lot of latitude to expand the number of genes — double them and the cell goes bankrupt. Yet eukaryotic cells can have ten times that number of genes.

But that assumes that all of the genes are being transcribed and translated all the time. This is certainly not the case.

There is also another important consideration with respect to genome size and that is cell cycle time. In general, the larger the genome, thew longer the cell cycle time. This may be critical in prokaryotes, but not so much in eukaryotes. Certainly there may be nucleotypic effects, so genome size increase is not without costs. However, smaller genomes mean shorter time for DNA replication and shorter cell cycle or generation times. This is probably one of the driving forces behind the reduction in animal mitochondrial genome size as well.

Lane addresses the issue of genome size/speed of cell division with respect to this question in his books.

amphiox said:

Lane addresses the issue of genome size/speed of cell division with respect to this question in his books.

Back when I read the paper in October I didn’t have the reaction I had here so I re-read it and discovered that my critique is more a reaction to Myer’s explanation than Lane’s hypothesis as expressed in Nature.

For example, Lane discusses the negative selection pressure on the size of the prokaryotic genome like this:

For four billion years bacteria have remained in a local minimum in the complexity fitness landscape, a deep canyon bounded on all sides by steep energetic constraints. The possession of mitochondria enabled eukaryotes to tunnel through this mountainous energetic barrier. Mitochondria allowed their host to evolve, explore and express 200,000-fold more genes with no energetic penalty. This is because mitochondria obliterated the heavy selection pressure to remove superfluous DNA (and potential proteins), which is among the most pervasive selective forces in prokaryote genome evolution44, 45, 46.

Eukaryotes harbour approximately 12 genes per Mb, compared with about 1,000 in bacteria. If an average bacterium had a eukaryotic gene density, at 6 Mb of DNA it would encode fewer than 100 genes. With only 0.08 pW Mb−1, it lacks the energy to support much regulatory or non-coding DNA. Bacteria must therefore maintain high gene density, around 500–1,000 genes per Mb, and do so by eliminating intergenic and intragenic material, including regulatory elements and microRNAs, by organizing genes into operons, and by restricting the median length of proteins47—all of which reduce the energetic costs. The high gene density and small protein size of bacteria can be explained in bioenergetic terms. In comparison, at a gene density of 12 genes per Mb and a metabolic power of 0.76 pW Mb−1, an average protozoan could in principle sustain nearly 350,000 genes, allowing it to evolve, express and explore novel genes and gene families, increase the size of proteins47, and invest freely in regulatory microRNAs48.

In my opinion Lane also does a better job in explaining why endosymbiosis is necessary. Namely, you need the following: small, high copy, bioenergetically specialized genomes and that’s only in mtDNA. Here’s Lane’s explanation why this is necessary. Note in the second to last paragraph another description of why you need to focus on replication rather than translation. Also note the last sentence where endosymbiosis does not make a fait accompli for complexity.

The main difference between endosymbiosis and polyploidy relates to the size and distribution of genomes over evolutionary time. In endosymbiosis, surplus organelle genes are lost or transferred to the host’s chromosomes, streamlining endosymbiont replication via cytoplasmic inheritance11, 17, 63. The outcome is a massive reduction in genome size, both in prokaryotic endosymbionts11 and organelles64, with a reciprocal relocation of genes in low copy number to nuclear chromosomes in the latter. By contrast, in giant polyploid prokaryotes, all genomes are essentially the same. Without cytoplasmic inheritance, no genomic specialization ensues.

In principle, prokaryotes could control respiration using specialized, membrane-associated plasmids that emulate organelle genomes in gene content and function. In practice, such plasmids are not found. Bacteria usually have small, high-copy-number plasmids that segregate randomly at cell division, or very few giant plasmids that co-segregate with chromosomes on filaments from midpoint65. For plasmids in a prokaryote to support electron flux as organelle genomes do, high-copy-number giant plasmids encoding components of the electron-transport chain would need to associate with the plasma membrane, and evolve counter to the tendency to segregate with size rather than function46. That no mtDNA-like plasmids are known indicates that high energetic barriers preclude their evolution: unlike organelles, which pay back energetically from the start, substantial energetic costs must be paid up front (high copy number of the correct plasmids, and the machinery to associate them with the membrane at regular intervals) before any energetic advantage can accrue.

The penalty for not having mitochondria or dedicated mtDNA-like giant plasmids is that Epulopiscium must replicate its 3.8 Mb genome hundreds of thousands of times every generation. This giant bacterium with 200,000 3.8 Mb genomes harbours 760,000 Mb DNA; a similarly sized eukaryote with 200,000 copies of an average mitochondrial genome must sustain only 6,000 Mb of DNA (and for small mitochondrial genomes potentially as little as 1,200 Mb). If the metabolic rate of Epulopiscium were around 0.01 W g−1 (similar to Amoeba proteus) and its mass 4,000,000 × 10−12 g, its metabolic rate would be 40 nW per cell, similar to eukaryotes. However, because Epulopiscium has thousands of complete genomes, this translates into only 0.075 pW Mb−1, similar to other bacteria. At a mean gene density of 12 genes per Mb, Epulopiscium could sustain fewer than 50 genes, and hence should have high gene density, typical of bacteria, despite its energetic tolerance for a massive amount of DNA. Bioenergetic considerations grant Epulopiscium lots of DNA per cell, but organized as complete compact prokaryotic genomes.

Thus, being large and having masses of DNA is not enough to attain complexity: cells need to control energy coupling across a wide area of membranes using small, high copy, bioenergetically specialized genomes like mtDNA (Fig. 2). Segregating the genes relinquished by the endosymbiont (mtDNA) into low copy number in the host’s chromosomes, specialization of the endosymbiont into an ATP-generating organelle50, 51 and increasing organelle copy number provides sufficient energy per gene to support the evolution, maintenance and expression of some 105 more host genes, affording the cell the chance—but not the necessity—of becoming complex.

Is this thread still alive? I’m sure PZ is 200 posts beyond this on Pharyngula.

Modern prokaryotes seem to experience or be descended from lineages that experienced very high negative selection for large genomes, and in particular, for non-coding DNA.

I say this because, for the most part, they don’t have any significant amount of non-coding DNA. In fact, they’re more likely to have overlapping genes.

They are also all haploid.

They also have mechanisms for extensive lateral genetic transfer, such as plasmids. Plasmids don’t really seem to be parasitic or infectious to speak of. Lateral transfer occurs in eukaryotes, but often due to viruses.

Eukaryotes are fundamentally diploid. There are polyploid forms and there are haploid forms in some lifecycles but they aren’t fundamentally haploid.

Diploidy may be as much of an issue as anything else here. With a “backup” copy of every gene, a lot more variance is tolerable.

I was always afraid of something like this happening: it turning out that a proper understanding of what the frell is going on in biology requiring economic reasoning.

Eric Means said:

I’m a lurker on this blog, an electronics engineer with a late-in-life-to-awaken fascination for evolutionary biology. Very happy to see Nick Lane’s books cited here. I’ve gobbled up most of the popular science books on evolution in recent years, and Lane is hands-down my favorite author.

PZ Myers does an excellent job of summarizing Lane’s idea here. I’d be interested to read others’ opinions of Lane’s musings on the origin of life from deep sea vents. The biochemistry, the geology, etc. Do his ideas hold water?

Lane is the best biochemist turned author since Isaac Asimov. :)

Actually those ideas originate with geochemist Mike Russell and others, foremost of whom is the same Bill Martin who coauthored with Lane the Eukaryote paper that’s the topic of the thread. Lane is the best champion of the idea to the public (and he’s co-published some papers contributing to the theory). His most footnote heavy paper on both abiogenesis and Eukaryote origin is “Chance or Necessity? Bioenergetics and the Probability of Life” in the August issue of the Journal of Cosmology.

There are LOTS of details to fill in, but the naturally chemiosmotic coupling of sulfur rich alkaline hydrothermal vent and carbonated iron rich Hadean ocean line up with the most ancient attributes common to free living organisms better than any previous theories. RNA World, Lipid World, and Wächtershäuser’s theory aren’t superseded by this, but incorporated.

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