Beauty’s meaning is more controversial. Here I wish to pursue just one idea: that it has something to do with physiological condition; that it is, indeed, a certificate of health. In its simplest form the truth of this idea is also quite self-evident. Clear skin, bright eyes and white teeth are manifestly signs of beauty and health. It is no accident that Brazilian men, glimpsing a beautiful carioca, sigh ‘Que saúde’ – what health. Whether particular facial proportions and symmetry signify health is, however, less obvious. Studies using computer-generated faces show that we perceive beautiful faces as being healthy ones. But searches for a correlation between the beauty and health of real people have found only weak and inconsistent effects.
Perhaps this is because beauty is no longer what it was. For all of human history, poor health has mostly been about nutrition and pathogens – a lack of the first and an excess of the second. Beauty was an indicator of the salubriousness of the environment or else the ability to resist its vicissitudes. To the degree that this is true, then the variance in beauty must be declining in the most developed nations at least, even as its mean increases. Goitres and cretinism may still afflict large parts of the world, but they no longer afflict the Swiss. The scars of smallpox have disappeared everywhere. Even in England most people now keep their teeth until they die. One wonders whether the diseases – filariasis, malaria, sleeping sickness, not to mention nutritional deprivation in its many forms – that afflict so many of the world’s children can be read in the symmetry and proportions of their faces if, as adults, they should have survived them. There is no doubt that prosperity exacts a cost to beauty in the form of obesity, dental cavities and stress. But if the balance of its effects is favourable, and it must be, then any classroom of American or European undergraduates contains an abundance of beauty that has never existed in human history before.
That may seem implausible, but only because we have little grasp of beauty’s advance. Beauty is like wealth. It increases over time, yet its distribution remains unequal. However much of it we have, it always seems that someone else has more. In part this is because beauty, as the consequence of health, is also the consequence of wealth. But suppose there existed a society so wealthy and egalitarian that, as far as pathogens and nutrition are concerned, all were equally healthy. A society of the sort approached by the Netherlands (but from which Great Britain and the United States remain woefully distant), in which the socioeconomic background of a child cannot be judged from his or her physical appearance alone. Would all be equally beautiful in such a society? Would beauty’s difference have disappeared? I doubt it. However beautiful the average Dutchman may believe himself to be, some of his compatriots will be more beautiful yet. I suspect that there is a residual variance in beauty that even the most controlled upbringing cannot eradicate. A residuum that lies in our genes.
The effects of poor childhood nutrition and exposure to pathogens upon the face may be uncertain, but the effects of mutations are not. When clinical geneticists attempt to classify the symptoms that their patients present, it is to the face that they first look. They are expert in recognising the subtleties that are often the only outward sign of deeper disturbances in the genetic order: shallow philtrum, low-set ears, upturned nose, narrow or wide-set eyes. Many, perhaps most, of the disorders that I have discussed in this book – from achondroplasia to pycnodysostosis – can be read in the face.
It seems that our faces are very vulnerable to mutation. Or perhaps we are just very good at reading mutation’s effects in them. Either way, it seems likely that mutation’s effects are written on all of our faces – not simply the faces of people with identified clinical disorders. I began this book by observing that every newly conceived embryo has, at an educated guess, an average of three hundred mutations that affect its health for the worse. It may seem impossible that we could, as a species, be so poorly. But a certain number of mutations are eliminated by selection in the womb. A woman who knows that she is pregnant has a 15 per cent chance of miscarriage; many more embryos must be lost to women who are unaware that they have conceived. More than 70 per cent of spontaneously aborted foetuses bear severe chromosomal abnormalities, and it is likely that many also bear mutations in particular genes. It is now widely supposed that miscarriage is an evolved device that enables mothers to screen for, and rid themselves of, genetically impaired progeny.
Mutation is a game of chance, one we must all play, and at which we all lose. But some of us lose more heavily than others. Some calculations hint at the distribution of our losses. If we suppose that, of the three hundred mutations that burden the average newly conceived embryo, five are lost from the population each generation by death (miscarriage, infant and childhood mortality), then the average adult carries 295 deleterious mutations. The least burdened 1 per cent of the population will have about 250 mutations, and the most burdened 342. Somewhere in the world there is a person who has the fewest mutations of all, about 191 of them.
These calculations confirm the intuition that no one leaves the genetic casino unscathed. But they are just educated guesses. They also take no account of the relative cost of each mutation. They are the equivalent of estimating gambling losses by counting the number of chips surrendered to the house without noting their value. It seems likely that the cost of most mutations is quite small. They give us minor ailments such as bad backs and weak eyes. I suspect that they also give us misaligned teeth, graceless noses and asymmetrical ears. If this is so, then the true meaning of beauty is the relative absence of genetic error.
There is, admittedly, very little evidence for this idea, at least in humans. Evolutionary biologists have long suspected that the peacock’s tail and the red deer’s roar are signals of genetic quality, and have amassed much evidence in the support of this theory, most of it weak. The mutational-load explanation of beauty is however consistent with our intuitions – or prejudices – about the distribution of beauty. If deleterious mutations rob us of beauty, they should do so with particular efficacy if we marry our relatives. Most novel mutations are at least partly recessive, and inbreeding should accentuate their negative effects as they become homozygous. There is no doubt that consanguinous marriages have a cost: the children of cousins have a 2 to 4 per cent higher incidence of birth defects than those of unrelated individuals. One wonders if such children would be judged less beautiful than their outbred peers as well. Pakistan, where around 60 per cent of marriages are between first cousins, would be a good place to look. Conversely, people of mixed ancestry, such as Brazilians, should show the aesthetic benefits of concealing their recessive mutations – Que saúde.
What makes physical beauty so wonderful? What enables it to take us by surprise, to prevent us from treating it with indifference no matter how saturated we are by the worlds of advertising and celebrity that have appropriated it, indeed made us suspicious of its power? If the answer that I have sketched contains any truth, then each image of a beautiful face or perfectly turned limb is not really about the subject that it appears to be, but rather what it is not. It is about the imperfections that are absent: 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. Beauty, Stendhal says, is only the promise of happiness. Perhaps. But it is equally the recollection of sorrow.
ACKNOWLEDGEMENTS
I have accumulated many debts while writing this book. My agent, Katinka Matson at Brockman Inc., first saw what Mutants might become. I thank her as well as Karen Murphy at Viking Penguin USA, Maarten Carbo at Contact, Netherlands and, most of all, Michael Fishwick at HarperCollins UK, whose faith in the book’s ultimate existence was tested but never faltered. Robert Lacey, also at HarperCollins, was a wonderful editor. My Dutch translator, Robert Vernooy, was an acute critic. Several friends and colleagues commented on part of the manuscript, among them:
Austin Burt, Arnold Heumakers, Barbara van Ijzeren, Marie-France Leroi, Jan-Roelof Oostra, Corinne Pernet and Jonathan Swire. Olivia Judson, Clare Isacke, Jennifer Rohn and Alberto Saez read and commented upon it all; I do not know how to repay them.
Many friends and colleagues answered specific queries, among them: Elizabeth Allen, Alan Ashworth, Peter Beighton, Chin Chiang, François Delange, Frank Dikötter, Saul Dubow, Ademar Freire-Macias, Frietson Galis, Jill Helms, Christiane Hertel, Annemarie Heumakers, Michael Hochberg, Beatrice Howard, Grace Ioannidou, Martin Kemp, Hannelore Kischkewitz, Deborah Posel, Liesbet Rausing, Raymund Roos and John Wilmoth. Jan-Roelof Oostra in Amsterdam and Cédric Cremiere and Jean-Louis Fischer in Paris were especially generous with their expertise in teratology and its history. Véronique Dasen in Fribourg told me about the teratology of the ancient world; Marta Lahr and Robert Foley at Cambridge showed me their wonderful collection of skulls; Yehuda Koren and Eliat Negev in Jerusalem told me about the Ovitz family in the Third Reich. I have not been able to do their scholarship justice. My pupils Anne Rigby and Sarah Ahmad told me of things that just had to go into the book; Carolyn Richardson and Irin Maier researched and translated texts. I could not have illustrated the book without the help of Miriam Guttierez-Perez at the Wellcome Library for the History of Medicine, London, and Laura Lindgren and Gretchen Worden at the Mütter Museum, Philadelphia.
My greatest debts, however, are to those around me: my colleagues at Imperial and the – sadly neglected – people in my lab; my friends – Austin Burt, Jim Isacke, Olivia Judson, Giorgos Kokkoris, Vasso Koufopanou, Michaelis and Katerina Koutroumanidis, Alexandra Meliadou, Jenny Rohn, Jonathan Swire, Liesbeth Verreijdt; and my family – Marie-France, Harry, Iracema, Joseph, most especially my parents, Antoine and Johanna. But above all it was Clare Isacke who sustained me while writing this book. It is dedicated to her with love.
NOTES
The clinical and developmental genetic literature is both vast and growing. However, I have attempted to give a guide to where the major results can be found and, occasionally, further details on particular topics. Beyond these notes, the most important source for those seeking further information about particular genetic disorders is Mendelian Inheritance in Man, an on-line database authored and edited by Victor A. McKusick and his colleagues at Johns Hopkins University, Baltimore, and supported by the National Center for Biotechnology Information, USA. It contains continually updated descriptions of each disorder, the mutations that cause them, and the clinical genetic literature. MIM can be found at http://www3.ncbi.nlm.nih.gov/Omim/. To assist those who wish to penetrate this difficult literature I give, for each syndrome and gene, the MIM numbers in bold so: achondroplasia (100800) is caused by mutations in FGFR3 (134934). Neither MIM nor this book should be used for self-diagnosis.
PROLOGUE
xiii Genetics, to quote one popular writer. Steve Jones, whose book The language of the genes (1993), HarperCollins, London, remains the best popular account of human population genetics.
xiv On 15 February 2001. The sequence of the human genome (International Sequencing Consortium 2001).
xv To learn from animals. See Gilbert (2000) p.361 for Leonardo’s cow placenta and Needham (1959) p.65 for Cleopatra’s alleged studies of human development.
CHAPTER I: MUTANTS
3 We had heard that a monster had been born at Ravenna. The monster of Ravenna has been much discussed. See Landucci (1542; 1927) pp.249–50 for a contemporary account of the monster. Jean Céard dicusses its evolution in his edition of Pare’s Des monstres (1573; 1971) PP.153–5; Niccoli (1990) pp.35–51 its political meaning; see also Fischer (1991) pp.54–6 and Daston and Park (1998) pp. 177–82. I suggest that the monster’s disorder is Roberts’s syndrome (268300), but others (Walton et al. 1993; Martinez-Frias 1993) have suggested cyclopia, sirenomelia or else hydrocephalus. All these diagnoses are guesses – which one you favour is a matter of which depiction of the monster you use, and which of its many odd features you believe are real.
6 In the sixteenth and seventeenth centuries. My description of Renaissance teratology is indebted to Park and Daston (1981) and Daston and Park (1998), though it has perhaps a more Whiggish flavour than theirs. See Boaistuau (1560, 2000) for a reproduction of an unusually beautiful teratological manuscript of the time, Melancthon and Luther (1523; 1?23) for the Monk-calf, and Paré (1573; 19?2) pp.3–4 for his list of the causes of deformity. For nineteenth-century views on maternal impressions see Gould and Pyle (1?97) and Bondeson (1997) pp.144–69. For the seventeenth-century teratologists see Aldrovandi (1642); the first edition of Liceti’s De monstrorum was published in 1616, but I have worked from the second (1634) edition, a synopsis and French translation of which is given by Houssay (1937). A brief account of Liceti’s life and work is given by Bates (2001).
8 There is a moment in time. For Sir Thomas Browne’s views on deformity in Religio medici (1654) see his Works (1904) volume 1, pp.26–7. For the shift in opinion of monsters from wrath to wonders of God see Park and Daston (19?1). For William Harvey’s writings on generation see Anatomical Exercises on the generation of animals; to which are added, essays on parturition; on the membranes, and fluids of the uterus; and on conception (1650) in his Works (1965). The quote, however, is from the 1653 translation by Martin Llewellyn as given by Needham (1959) p.134.
10 It was, however, a contemporary of Harvey’s. For Bacon’s division of science see Bacon (1620, 2000) pp.14?–9 and 223–4. For an account of Renaissance collections of marvels see Daston and Park (199?) pp.255–301. Harvey, John Aubrey tells us, thought little of Bacon as either a philosopher or a writer, but Harvey espoused very Baconian sentiments when he wrote: ‘Nature is nowhere accustomed more openly to display her secret mysteries than in cases where she shows tracings of her workings apart from the beaten path.’
13 Most of these people have mutations. On-line Mendelian Inheritance in Man lists about a thousand genes that cause phenotypic variation, be it pathological or not (e.g. brown eyes).
16 If there is no such thing as a perfect or normal genome. The estimate of how many times each of the genome’s base-pairs have mutated in the last generation alone is given by Kruglyak and Nickerson (2001). The estimate of 65 per cent of genes as having polymorphisms applies to alleles defined by non-synonymous polymorphisms only. Conversely, my claim that most genes have an overwhelmingly common variant comes from the observation that 35 per cent of genes are monomorphic, and that in the known polymorphic ones, the minor alleles usually have a frequency below 5 per cent. Again, this applies to non-synonymous polymorphisms only (Cargill et al. 1999; Stephens et al. 2001).
18 Each embryo has about a hundred mutations. Eyre-Walker and Keightley (1999) estimate the rate of production of deleterious mutations in humans. Their estimates are consistent with those from Cargill et al. (1999) and Stephens et al. (2001) obtained by other means. Crow (2000) reviews the fitness effect of novel mutations.
CHAPTER II: A PERFECT JOIN
25 The Parodis arrived in Paris. Contemporary accounts of Ritta and Christina Parodi are given by Anon (1829 a; b; c); Saint-Ange (1830); Janin (1829) and Danerow (1830). Later accounts by Thompson (1930; 1996) p.84 and Bondeson (2000) pp.168–73.
26 The first cut exposed the ribcage. The major anatomical monograph on Ritta and Christina is Serres (1832). É. Geoffroy Saint-Hilaire (1829) considers the girls in a small paper and I. Geoffroy Saint-Hilaire (1832–37) in volume 3 pp. 161–74 of his synoptic teratology.
27 The oldest known depiction. The Anatolian statue, from the Catal Hüyük site, dates from around 6500 BC; the Australian rock carving from 3–4000 BC. For the Molionides brothers, and a more general discussion on con joined twins in ancient Greek art, science and myth, see Dasen (1997; 2002). For Renaissance teratologies see Paré (1573; 1982) and Boaistuau (1560; 2000) pp.134–7. For the Montaigne quote see Montaigne (1603; 1998), and for their intellectual context Daston and Park (1998) pp.205–7. The conflict between Duverney and his rivals is dis
cussed by Fischer (1991) pp.71–4 and Wilson (1993) pp.150–9. For the intellectual context of preformationism and epigenesis see Needham (1959) chapters 3 and 4, and Pinto-Correia (1997).
32 What makes twins conjoin? Conjoined twins occur at a frequency of 1 in 100,000 live births; monozygotic separate twins occur at a frequency of 1 in 300 live births. For Aristotle on conjoined twins see The generation of animals in his Complete works volume 1 pp.1192–1996. See Friedman (1981) pp.180–1 on baptising conjoined twins.
33 Until recently, the origin of conjoined twins. For a typical medical embryology textbook account of conjoined twinning see Sadler (2000) p. 155. Although most conjoined twins seem to be monozygotic (they are nearly always of the same sex) there is at least one case that has been shown, by genetic tests, to be the result of a fusion between dizygotic embryos (Logroño et al. 1997). For the sex ratios of conjoined twins see Steinman (2001 a; b). Spencer (2000 a; b; 2001) gives a detailed critique of the fission model of conjoined twinning based on the geometry of the joins. See Martin (1880) pp. 153–69 for the evolution of theories of the causes of conjoined twins.
35 On the seventh day. For a description of early human embryogenesis see Beddington and Robertson (1999) and Sadler (2000).
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