Customer Reviews:
 Building from basics July 24, 2008
6 out of 6 found this review helpful
It's a sad commentary that any book on biology published in the US must devote pages and ink to refuting the rants of "anti-Darwinists" in that nation. Richard Dawkins ["The Selfish Gene"] holds a chair at promoting "Public Understanding of Science" at Oxford. Carroll, whose role as a professor of genetics provides firm underpinning, is establishing himself in a similar niche in the US. This book is an example of how well he can fulfill that undertaking. In his previous work "Endless Forms Most Beautiful", Carroll described some of the manifestations of the genome's activities. In this book he delves more into today's operations within the genome and how those were derived from the distant past.
The author's selection of examples to explain DNA's role in life may seem bizarre at first glance: "icefish" carrying "anti-freeze" in their bodies, what humble pigeons tell us about life, and what human skin colour really means. Each of his examples carries an historical record of how they came to be that way. Evolution, he reminds us, builds upon what went before. Once a trait, no matter how "primitive", is established, mutation may improve its possibility of success down the generations. "Primitive", by the way, is a term Carroll shuns, since those traits that survive are clearly best suited for that organism in that time and place. It's important to understand that, since a good many health issues relying on genetic research must be considered in the light of environmental conditions. Infectious organisms change to cope with treatment and medicines must be developed to cope with their adaptations. This is the record of life, with the earliest genes bifurcating to form new traits with the passage of time and new conditions.
Carroll's chapters address a number of life's little quirks. There's a discussion of how populations shift and divide when conditions change [stickleback fish], an account of the discovery and significance of "thermophilic" microbes found in Yellowstone Park hot springs, and how Soviet politics dabbled in science to virtually destroy agriculture in the communist empire. Every chapter contributes to learning how genetics works and why some understanding of the processes involved is important. For this reviewer, however, the author's presentation of the historical beginnings and development of eyes remains the most fascinating. Although Darwin was greatly disturbed that he couldn't conceive how eyes could have evolved, modern research has determined the process. In Carroll's hands, the mechanism producing eyes is clearly revealed and almost exquisitely explained. He shows how light perception across various species provides clues to past ocular structures. Once you have read this section, you will never be able to consider "the" eye [which is too often presumed to be human] in the same way again.
The book's close, which Carroll clearly feels necessary, is somewhat depressing. Evolution shouldn't need defending - it's clearly how life works. The author has the good sense to apply practical logic in itsdefence, using the issues of over-hunting and -fishing to show how humans indifferent or hostile to the concept of life changing over time are driving evolution themselves. He deems the result of that indifference "Unnatural Selection" since it is driving down the size and adaptability of more than one species. There are plausible arguments for starting this book with the final chapter. No matter where started, however, this is a book to be read. [stephen a. haines - Ottawa, Canada]
How DNA supports the fact of biological evolution July 16, 2008
3 out of 3 found this review helpful
Most of this book is a primer on how the study of DNA code from various species sheds light on the evolutionary process. The text is as clear as such a text can be considering how abstract the DNA sequences are to even the well educated reader. There are numerous charts and tables, drawings, black and white photos (and some color plates) and such in this timely, handsome and well-presented book to guide the reader. I only wish that I could have grasped the details in a more concrete manner.
DNA codes for proteins, of which there are vast numbers. These proteins are formed from amino acids of which life uses twenty, and in turn these amino acids are called up by the sequence of letters in the code. Presumably (Carroll does not make this clear) as the zygotic cell divides, working its way to the composition of the complete organism, the DNA code is read in sequence like a tape fed into a bar code. First this protein and then that protein and then still another is made and somehow strung together in an exacting order so that, voila! a massively complex organism is constructed. What is not in this book is an explanation of how these proteins know where to go and when. Presumably that knowledge is part of the very sequence of the code, or perhaps it is implicit in the positions in space of the proteins relative to one another. In others words, the DNA code is only the most obvious and "visible" part of the microscopic reproductive process.
If you are like me and are looking for the same sort of explanation, this book will be of limited value. Prof. Carroll's purpose is not to make transparent the reproductive process at the chemical level. His purpose--and a laudable one it is--is to show how DNA analysis is yet another piece of evidence pointing to the truth of biological evolution. That is why he uses the word "forensic" in the subtitle.
One of the most powerful uses of DNA is in reconstructing the so-called "tree" (or "bush") of life. Carroll shows how it is now clear beyond almost any doubt that our closest relatives are chimpanzees and bonobos followed by the other great apes and then monkeys. He shows how DNA analysis can also (and by the same logic) be used to show the relative age of species. Interesting is the discovery of how exactly similar are some sections of code in diverse species, indicating that such code is very ancient. In fact Carroll points to "immortal" sequences of code that have resisted all attempts at corruption or mutation. He explains that such code is so nearly indispensible to living forms that natural selection is, and has always been, active in keeping it intact.
In this regard (and moving to the latter chapters of the book) we find a particularly delightful refutation of one of the notions of "Intelligent Design." Carroll quotes perhaps the best known of the intelligent designers, Dr. Michael Behe, as writing:
"Suppose that nearly four billion years ago the designer made the first cell, already containing all of the incredibly complex biochemical systems discussed here and many others. (One can postulate that the design for systems that were to be used later, such as blood clotting, were present but not `turned on.' In present-day organisms plenty of genes are turned off for a while, sometimes for generations, to be turned on at a later time)." (p. 244)
How brilliant this sounds! However Carroll writes:
"This is utter nonsense that disregards fundamentals of genetics. Dr. Ken Miller of Brown University has described this scenario as `an absolutely hopeless genetic fantasy of pre-formed genes waiting for the organisms that might need them to gradually appear.' As we saw in chapter 5, the rule of DNA code is use it or lose it. The constant bombardment of mutation will erode the text of genes that are not used, as it has in icefish, yeast, humans, and virtually every other species. There is no mechanism for genes to be preserved while awaiting the need for them to arise." (p. 244)
Indeed, if Behe were correct, there would be in virtually all species "silent pre-formed genes" waiting to be called upon. There aren't.
In the chapter entitled "Seeing and Believing" Carroll recalls Louis Pasteur's struggle to demonstrate to non-seeing and non-believing doctors that childbed fever was caused by their dirty hands. He reprises the horrific and bizarre story of the Soviet head of (political) biology Trofim Denisovich Lysenko who denied genetics, and how Stalin's support of him led to massive failures in agriculture and subsequent starvation. He further recalls how Mao Zedong, using the same unscientific ideas, sponsored massive starvation in China due to crop failures.
What Carroll is getting at is that political corruption of science can be very dangerous. In the United States today under the power of the Bush administration, faith-based (and corporate-sponsored) science is denying global warming and other deleterious effects of rampant pollution. This sort of science denial is likely to lead to human suffering and death, just as did the communist denial of genetics.
Superb June 22, 2008
4 out of 4 found this review helpful
All species' lifeforms are encoded in DNA sequences. In Humans this is 7 billion characters long. During replication, not all characters are copied correctly. For example, in humans it is estimated 125 or so are copied incorrectly. In certain cases this can mean the resultant amino acids and proteins, which the DNA encodes will be different. This is a mutation. If the mutation provides an advantage, natural selection will mean it is probable it will propagate throughout the species.
DNA provides detail of the mirco mechanisms and strong evidence when critical events happened in evolutionary history. We don't actually need a fossil record to explain evolution. This is the main theisis in this book.
For example, Old World Monkeys and Apes have trichromatic vision whereas New World monkeys are just dichromats. Why? When? How? Carroll explains all in succinct detail by locating the exact location of the relevant gene and then working through the sequence of events.
He uses simple mathematics, running through some probability examples and statistics analysis to the point that one has a full understand of the mirco details, feeling there are no "missing links". It's reductionism at its very best.
He then shows why understanding infectious diseases requires understanding evolution. We are involved in germ warfare. For example, in areas where malaria or typhoid fever is endemic, the genetic profiles of humans shows that they have evolved genes which provide resistance to some forms of these diseases. The problem of course is that these diseases are also evolving (not just to human resistance but to the antibiotics that are used to treat them). Our hole approach to combating these diseases is shaped by our understanding of evolution - right at the level of DNA. For example, it is the reason why triple antiretroviral drugs are used in treating HIV AIDS.
Carroll is superb at explaining micro details. The only criticism I would have is a quick run through speciation and the Popperian scientific method would have helped many who do not understand the big picture, how evolution explains new species being created and how the scientific method validates that explaination. Even though 20 minutes on google will give all that, it would have been helpful for those who do not have any scientific acumen.
The book concludes with some of the challenges facing Science. This may manifest in many forms from political circles to religious fundamentalists. When one factors in pertinent realities such as climate change it only becomes all too obvious how important it is we have a scientific understanding of the world and we make the best judgments from that.
I have read several books on evolution and this right up there with the best. It's just as good as anything I have read from Dawkins and doesn't have any of the caustic anti-religion undertones. He explicitly states that the Pope John Paul II publicly accepted evolution as do most Protestants Churches; Christian creationists and fundamentalists are really only a minority.
It is a book which contains superb explanations of the micro details of evolution. It is full of helpful diagrams, charts and graphs which really help understand the concepts being explained. Don't get it from the library, buy it because you'll want to keep it.
 Genes on the loose, but with a purpose June 17, 2008
3 out of 3 found this review helpful
Genetics science has mushroomed the last 50 years, overturning many cherished preconceptions in biology and other Natural Sciences, while buttressing other theories with an abundance of hard scientific evidence. Charles Darwin's Theory of Evolution through Natural Selection has been in the later category, with its core assumptions confirmed by the new data about DNA structure, history and function.
The book is composed by a series of essays on the nature and function of genes within the DNA code, embedded in the cells of every living organism. The author offers ample evidence, from experimental data, about how exactly the workings of genes are ultimately responsible for the shaping and evolution of the Natural World around us. The point of the whole demonstration is to establish that Natural Selection mechanisms, as defined by Darwin about 150 years ago, are alive, well and firmly supported by the new data.
The text is aimed at the general public but some knowledge in basic biology and DNA function will help the reader to follow the arguments more closely. It is not a prerequisite though, since the author explains thoroughly the more stringent points, with help from the illustrations.
The last part of the book is the most disappointing, since it involves the denial of evolution, based on religious grounds, and a dire comment on the continuing destruction we inflict to the planet's ecosystems. The author's position, and one that I personally agree totally with, is that alarm bells are already sounding in many quarters and we no longer have the option of intellectual blindness.
A robust case for Darwinians June 8, 2008
4 out of 12 found this review helpful
This was an excellent book. Very well written in terms of style and obviously well researched.
The surprise will be for you to know that I believe in Special Creation, but I can still value a good book on the Darwinian perspective and contemplate the potential challenges to what I believe.
I still think there is a huge misunderstanding in definitions and terms. An Example would be the case of fruit fly wings (but the principle applies to other cases mentioned); even creationists accept this as 'evolution' if this is how it is defined!
What Darwinism (in my view) still fails to explain is the full diversity that exists in nature, from scratch - beyond 'micro-evolution', and why stasis is the predominant feature of the fossil record.
Interestingly, Sean Carroll emphasises the importance of the fact that we are "stewards of our planet". I agree; and this was precisely the expectation that God had of mankind. Commercial greed and self-interest (amongst other things) has got in the way - but this cannot reasonably be laid at the feet of all those that believe in creation (as obliquely suggested on the final page).
However, I would recommend that all creationists should read this book; eat the meat and spit out the bones.
I hope that this will be found to have been of value to other prospective readers.
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