Mutants: On Genetic Variety and the Human Body

"Mutants" is part side-show and part genetic crapshoot where the mutated gene almost always loses. The author states that on the average, 300 mutations burden each newly conceived embryo. Five of the mutations won't make it into the general population because of miscarriage and childhood deaths---"No one leaves the genetic casino unscathed." Being born with three sets of eye-lashes, an extra set of ears on one's neck, or in my case, crooked little fingers, are very benign mutations compared to what can and sometimes does go wrong.The primary theme of this elegant, engaging book is that mutations are the signposts that can be used to determine exactly where in the morphogenesis of an infant, something went physically or genetically astray.Chapter 1, "A Perfect Join (On the invisible geometry of embryos)" takes the reader on a tour through the first few hours and days of a fertilized egg. Conjoined twins are an example of what can go wrong with the developmental mechanics within the womb. One unfortunate baby was born with 21 partially developed twins (determined through a leg count) in his skull. However, the main thrust of this chapter, using conjoined twins as an example of the process gone wrong, is the search for an 'organizer': that which informs the cells what to do, what to become, and where to go. It is a process that is part mechanical, part chemical, and part sheer dumb luck. As the author puts it: "The power of cell-cell adhesion to mould the developing body is startling."In the next chapter, the author examines the powerful homeotic genes and signaling proteins such as 'sonic hedgehog,' employing some gruesome examples of what can go wrong during the formation of the neural tube and other body parts. Human and animal Cyclops, as well as other mutations such as 'mermaids' are outcomes of control processes gone wrong. Sonic hedgehog-defective infants have a single cerebral hemisphere, hence one eye. "Mice in which the sonic hedgehog gene has been completely disabled have malformed hearts, lungs, kidneys and guts. They are always stillborn and have no paws..."I certainly wouldn't recommend this book to a pregnant friend. It's frightening enough to have a vague notion of what might go wrong, without this author's meticulous gene-by-gene guide as to the results of many mutations.Limb buds, skeletons, growth, gender, and skin color are all viewed in turn, through the distorting lens of genes gone wrong. We are introduced to pigmies, piebalds, cretins, and castrati.The penultimate chapter, "The Sober Life (on Ageing)" is especially interesting because ageing is something we all do regardless of our original mutational burden. The author raises the interesting question as to whether death is just another genetic engineering problem. "Were it not for ageing's pervasive effects, 95 per cent of us would celebrate our centenaries; half of us would better the biblical Patriarchs by centuries and live for more than a thousand years."Sir Peter Medawar was the first to suggest that mutations causing fatal errors in old age are not necessarily selected against. Once we've bred and raised our children, what use has nature for us?The final chapter, "Anthropometamorphosis (an Epilogue)" ends rather wistfully with a discussion of beauty, and why it may be important for the survival of a species. Beauty is defined as the absence of imperfections: "the machine errors that arise from the vicissitudes of the womb, childhood, maturity and old age, that are written all over our bodies and that are so ubiquitous that when we see someone who appears to have evaded them, however fleetingly, we pause to look with amazed delight."Read "Mutants" and you may also find yourself pausing, and looking about with amazed delight. Armand Marie Leroi does not exploit freaks of mutation so much as he weaves them into the story of each of our individual lives.

This is a very readable book, only getting too technical once or twice, but for the most part fully explaining concepts for his readers.Leroi bases his study of mutations in human beings on the philosophy of Francis Bacon. Bacon helped establish the principles by which the scientific inquiry of the natural world was to be conducted. Bacon saw that natural history can be divided intot he study of normal nature, aberrant nature, and nature manipulated by man. Leroi writes: "Centureies ahead of his time, Bacon recognized that the pursuit of the causes of error is not an end in itlsef, bur rather just a means. The monstrous, the strange, the deviant, or merely the different, he is saying, reveal the laws of nature. And once we know those laws, we can reconstruct the world as we wish."The range of Leroi's knowledge is considerable. The story repeatedly drew together the fields of philosophy, anthropology, history, and molecular biology.Leroi is the one of the first to discuss that in Africa the Delta 32 polymorphism of the CCR5 gene is currently increasing in frequency because it confers resistance to HIV. We know that CCR5 in some lucky persons of Northern European background gives them some protection against HIV infection. However this trait is so rare among Africans that I suspect the increase will not make significant changes in the grim outlook for sub-Saharan Africa.The book is actually hopeful even though it discusses the many ways that we as humans can go genetically 'wrong'. Leroi states: "The aveage newly conceived human bears three hundred mutations that impair its health in some fashion."Leroi's historic studies add much to the book. He uncovers the range of enlightened thinkers who saw human mutations, not as the work of the devil, but as opportunity to study God's methods. For example he quotes Montaigne: "Those whom we call monsters are not so with GOd, who in the immensity of his work seeth the infinite forms therein contained."Of course there are times that the book makes your hair stand on end. For example: "In 1982, a thirty-five-year-old Chinese man was reported with a parasitic head embedded in the right side of his own head. The extra head had a small brain, two weak eyes, two eyebrows, a nose, twelve teeth, a tongue and lots of hair. When the main head pursed its lips, stuck out its tongue or blinked its eyelids, so did the parasitic head; when the main head ate, the parasite drooled...A Dutch child born in 1995 had the remains of twenty-one foetuses (as determined by a leg count) embedded in its brain."There is a very interesting case study of the artist Henri de Toulouse-Lautrec. "By the time he was seven his mother had taken him to Lourdes, where she hoped to find a cure for some vaguely described limb problem... By the age of ten he was complaining of constant severe pains in his legs and thighs, and at thirteen minor falls caused fractures in both femurs which, to judge from the length of time during which he supported himself with canes, took about six months to heal. He would use a cane nearly all his adult life. Laurterc also undertwent some unusual facial changes. He developed a pendoulous lower lip, a tendency to drool, and a speech impediment rather like a growling lisp, and his teeth rotted while he was still in his teens."The examples continue to build on each other, offering new inforamtion and insight throughout the book.

I read this years ago after visiting the Mütter Museum and the information has stuck with me since. I am not of the scientific mind but this was fascinating and easy to understand the science of gene mutation. Years after reading my husband's cousin has a kid with an extra toe and I can explain what happened in womb to cause this. This book was a fascinating read.

Every once in a while I come across a science book by accident that are absolutely incredible. This is one such book. I teach physiology and pathophysiology at a university in Utah, but I always am looking for good books on genetics. I liked the way the author approached this from a different and less straight-forward point. In using people with differences such as children with one eye that we call 'cyclops' and explaining how things go wrong in the genes, Leroi provides an excellent illustration of what needs to go right in the body in order to achieve an acceptable two eyes in the normal face. How it fails, brings on the cyclops condition.I always mix history with my teaching about the body, because in neuroscience (my background) you learn the more ways you connect information to multiple parts of the brain through using stories, humor, etc the more likely the students are to remember what they are learning. That's what this book provides. Usually genetics can be a very long-winded and difficult thing to understand. But books like this makes much of this information available to everyone in a different format. I had to laugh with another reviewer who stated if her textbooks were like this she would actually read them. This is so true about textbooks, and I've been saying this for years. People who write textbooks, write them for their peers and not for the students!

it could have a higher quality publishing but the content is good

Great book.

Most of humans have an average, "normal" body - ten fingers, two hands, one nose, two eyes, two ears, etc. We are so used to this setup that we forget that development and life is an incredibly complicated process, requiring thousands of genes to work as coordinated teams to shape various cells, tissues and organs. And as is often the case with complicated things in life, they can go wrong. This book is a fascinating, albeit heart-breaking tour of some quirks of mutations, or mistakes in our DNA, that can lead to defective systems, whether they are our bones, eyes, or our nether regions (yikes!). Highly recommended.

Il testo passa in rassegna diversi "tipi" di freaks, analizza la possibile origine clinica e gli aspetti mitologici e archetipali. Ma le immagini sono pochissime e di scarsa definizione. Il testo vale comunque.

Decent quality.