Nick Lane

I found myself thinking about one of the chapters in this book, years after I had finished the book. But alas, I could remember the basics about muscle fibres but not the name of the book so when I went searching for it in my collection I had difficulties. However, I just re-discovered it and find it still as arresting as i found it the first time around. I'm really impressed with Nick Lane. He's a biochemist with a solid background in research and the current book won him many awards ...in eluding the royal Academy award for Science books in 2010. (Is it already that old?) He uses 10 inventions of evolution to elucidate life as we know it. They are.
1. the origin of life ....a reasonable overview and he seems to come down on the side of white (alkaline) smokers on undersea vents as the likely place where life originated. (I'm not so sure and note that he seems to entirely ignore the work of Cairns-Smith and a possible role for clay minerals as templates).
2. DNA.....which is mainly about routes for the possible evolution of RNA in the alkaline smokers and transformation into DNA. Quite fascinating. Lots to learn here.
3. Photosynthesis....Lane has written a whole book about oxygen so no surprise here that the photosynthesis story is about the role of electrons dropping to low energy levels (releasing energy) and being kicked back up to higher levels by more energy.....releasing oxygen in the process. (I must get his book on oxygen).
4. The complex cell...another masterful description of the biology of the cell ..but with only passing acknowledgement to Lyn Marguli's ideas about chloroplasts and mitochondria being organisms that were absorbed into the cell in a symbiotic relationship.
5. Sex...some interesting statistical stuff here but he makes the point that all eucaryotes: all plants, animals, algae, fungi, protists have sex but not bacteria...and huge numbers of genes were transferred to the cell by the absorption of mitochondria.
6. Movement..it's this chapter that stayed so long with me. The big change that came after the great Permian extinction was motility and motile organisms.....and movement requires muscles...converting chemical energy into mechanical force. Because of their great interest to me, I'll attach some more detailed notes on these chemical/protein mechanisms towards the end of this review.
7. Sight and the evolution of the eye....a beautifully written chapter ...full of interesting insights...like the trilobites use of mineral calcite lenses and in 2001 a living brittlestar was found with calcite lenses on its arms.
8. Hot blood...well I found out there that large animals generate more internal heat and large alligators are technically cold blooded but generate enough heat to be borderline hot-blooded
9. Consciousness...makes the point that the brain has obviously evolved ...so this would imply that "mind" has also evolved ....undermining Pope John Paul's message to the Pontifical Academy of Sciences that evolution was ok but the mind of man was above all of that (or words to that effect).
10. Death...some interesting observations on extending life spans. Makes the point that most diseases come with old age....postpone the biological old age and you postpone the diseases (and death).
And, as promised above, here are some nuggets that I've extracted from the chapter on movement that I found so fascinating.
"One meticulous study by the geneticists Satoshi Ōta and Naruya Saitou, at the National Institute of Genetics, Mishima, (I’ve walked by it many times....a lovely setting with views of Mt Fuji) Japan, showed that a selection of proteins in the skeletal muscles of mammals are so similar to those in the striated flight muscles of insects that both must have evolved from a common ancestor of vertebrates and invertebrates, living some 600 million years ago.

Jellyfish, it seems, also have striated muscles that are minutely comparable with our own. So both smooth muscle and striated muscle contract using a similar system of actin and myosin, but each system apparently evolved independently from a common ancestor that possessed both cell types - a common ancestor numbering among the earliest of animals, from a time when jellyfish were the acme of creation.

we now know, for example, that the gene sequences of yeast and human actin are 95 per cent identical.' And from this perspective, the evolution of muscle looks very different. The same filaments that power your muscles power the microscopic world of all complex cells. The only real difference lies in their organisation.
A set theme, the motor interactions between myosin and actin, for instance, is varied with the endless imagination of natural selection, to arrive at a breathtaking array of form and function.......
All the traffic of the cell is borne by protein motors that work in a broadly similar manner. First is myosin, which cranks up and down the actin filaments, just as it does in muscle. But here the variations begin. In muscle, the myosin heads spend nine tenths of their time detached from the actin filaments;

How did this great parade of motor proteins come to be? There is nothing that compares with it in the world of bacteria. Nor are actin and myosin the only motoring double-act in eukaryotic cells. A second family of motor proteins, called the kinesins, operates in much the same way as the myosins, in a hand-over-hand manner up and down the sky-wires of the cytoskeleton. In the case of the kinesins, though, the sky-wires in question are not the thin actin wires, but higher-bore tubes, known as microtubules, which are assembled from subunits of another protein called tubulin.

At the detailed level of their gene sequences, the two main types of motor protein, the myosins and the kinesins, have virtually nothing in common......Here and there are points of similarity, but for a long time this was taken to be either chance or a case of convergent evolution. Indeed the kinesins and myosins looked to be a classic case of convergent evolution, where two unrelated types of protein became specialised for a similar task, and so developed similarities in structure, just as the wings of bats and birds evolved independently to converge on similar solutions to the common challenge of flight.

On the basis of crystallography, then, we know that the myosins and kinesins did indeed share a common ancestor, despite having so little in common in gene sequence. Their three-dimensional shapes show many points of folding and structure in common, right down to critical amino acids being preserved in space with the same orientation. This is an astonishing feat of selection: the same patterns, the same shapes, the same spaces, all are preserved on an atomic level for billions of years.....

The shape of all eukaryotic cells, from long and spindly neurons to flat endothelial cells, is maintained by the fibres of the cytoskeleton; and it turns out that much the same is true of bacteria.
For generations, biologists ascribed many bacterial shapes (rods, spirals, crescents, and so on) to the rigid cell wall bounding the cell, so it came as a surprise in the mid-199s to discover that bacteria have a cytoskeleton too. This is composed of thin fibres that look a lot like actin and tubulin...... As with motor proteins, there is little genetic resemblance between the bacterial and eukaryotic proteins.......yet.. The bacterial and eukaryotic protein structures are virtually superimposable, with the same shapes, the same spaces, and a few of the same critical amino acids in the same places. Plainly the eukaryotic cell skeleton evolved from a similar skeleton in bacteria.

In short, the cytoskeleton is motile in its own right. How did such a thing come to be?
Both actin and tubulin filaments are composed of protein subunits that assemble themselves into long chains, or polymers. This ability to polymerise is not unusual; plastics,..... Something similar [spontaneous polymerisation] must have happened in the case of the cytoskeleton proper, long ago. The units of actin and tubulin fibres are derived from ordinary proteins, with other functions about the cell. A few trifling changes in their structure, as happens with the variant haemoglobin, enabled them to assemble spontaneously into filaments. Unlike sickle-cell anaemia, however, this change must have had an immediate benefit.

And so the majesty of motility, from its most elementary beginnings, to the many-splendored power of skeletal muscle, depends on the workings of a handful of proteins, and their endlessly varied forms........ Some intriguing puzzles, when answered, may shine a brighter light. In bacteria, for example, the chromosomes are drawn apart using actin filaments, whereas the tightening that divides cells during replication is achieved with tubulin microtubules. The reverse is true of eukaryotic cells. Here, the scaffold of the spindle, which separates the chromosomes during cell division, is composed of microtubules, while the contracting corset that divides the cell is made of actin. When we know how and why this role reversal took place, we'll certainly have a better understanding of the detailed history of life on earth..... The ancestor of all living eukaryotes was motile. Presumably motility brought with it big advantages"
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All in all, it fulfils some of the promotion quotes on the rear cover, like "If Charles Darwin sprang from his grave, I would give him this fine book to bring him up to speed" and "A science book that doesn't cheat: the structure is logical, the writing is witty, and the hard questions are answered"....I would agree with that. Five stars from me.… (plus d'informations)

Nick Lane is a biochemist and the first Provost’s Venture Research Fellow at University College London. This book, which the author describes as “grand in scope,” covers much of what is understood about the multidimensional phenomena we call “biological Evolution.”

Lane writes about ten aspects of evolution that he refers to as “inventions.” He clarifies his concept of invention as “the original contrivance or production of a new method or means of doing something, previously unknown; origination, introduction.” He emphasizes that in the case of evolution, these phenomena, all of which embody some form of design, occur naturally without an inventor or intelligent design.

To qualify on his list of seminal events in life’s history, the invention had to meet four criteria. First, the invention had to revolutionize the living world. Second, it had to be of surpassing importance today. Third, it had to be a direct outcome of natural selection rather that, say, cultural evolution. And fourth, it had to be iconic in some way.

This is not easy reading. Lane engages the reader at a fairly sophisticated level.

For example, he first discusses the very origin of life. He debunks the once popular theory that life arose from a “primordial soup” that was energized by lightening for thermodynamic reasons. Instead, he looks to volcanic activity on the sea floor as a source not only of energy but of the chemical building blocks for primitive life through the operation of the so-called Krebs cycle. In his view, the last common ancestor of all life on earth was not a free-living cell “but a rocky labyrinth of mineral cells, lined with catalytic walls composed of iron, sulphur and nickel, and energized by natural proton gradients. The first life was porous rock that generated complex molecules and energy, right up to the formation of proteins and DNA itself.”

Informative and highly recommended.

(JAB)… (plus d'informations)

One can study the biochemistry of photosynthesis in some detail and be unaware of the different pathways that exist and existed in different organisms, of its effect on the color of the sky, of its effect on the structural components of large plants and animals, and of the peculiarities of its evolutionary origin. Nick Lane gives a brilliant overview of the nature, significance and origin of the 10 greatest inventions of evolution including, the origin of life itself, DNA, photosynthesis, the eukaryotes, sex, movement, sight, warm bloodedness (homeothermy), consciousness, and death. I found the degree of detail to fit well with the text's readability and I was uniformly impressed with the author's knowledge and presentation. The relative low point, for me, was the chapter on consciousness. There is a great deal of interest there, but I think I am a little more radical than the author on this topic; he blows off Dennett with a single paragraph and he ends his discussion of the tragic case of a girl with hydranencephaly by stating that if it is the case that if the roots of consciousness are not to be found in the cerebral cortex, "then the neural transform, from firing to feeling, loses some of its mystique". Yes, that's what Dennett says, and it loses all of its mystique.… (plus d'informations)