Genes, Chromosomes, and Disease From Simple Traits, to Complex Traits, to Personalized Medicine

by Gillham, Nicholas Wright

• ISBN13: 9780137075447
• ISBN10: 0137075448
• Format: Hardcover
• Copyright: 2011-06-09
• Publisher: FT Press

Summary

This readable overview covers the rise of medical genetics through the past century, and the eugenic impulses it has inspired. Nicholas Gillham reviews the linkages between genes and disease; ethnic groups' differential susceptibility to genetic traits and disorders; personalized medicine; and crucial social and ethical issues arising from the field's progress.

Author Biography

Nicholas Wright Gillham is James B. Duke Professor of Biology Emeritus at Duke University. Although his specialty was organelle genetics, he has long been interested in eugenics, human genetics, and their history. His books include Organelle Genes and Genomes (Oxford University Press, 1994) and a biography, A Life of Sir Francis Galton: From African Exploration to the Birth of Eugenics (Oxford University Press, 2001).

Table of Contents

Preface	p. ix
Hunting for disease genes	p. 1
How genetic diseases arise	p. 25
Ethnicity and genetic disease	p. 55
Susceptibility genes and risk factors	p. 81
Genes and cancer	p. 103
Genes and behavior	p. 129
Genes and IQ: an unfinished story	p. 151
Preventing genetic disease	p. 175
Treating genetic disease	p. 199
The dawn of personalized medicine	p. 235
Postscript: a cautionary note	p. 249
References and notes	p. 253
Glossary	p. 293
Some useful human genetics Web sites	p. 307
Acknowledgments	p. 309
About the author	p. 311
Index	p. 313
Table of Contents provided by Ingram. All Rights Reserved.

Excerpts

Genes, Chromosomes, and Disease: From Simple Traits, to Complex Traits, to Personalized Medicine Genes, Chromosomes, and Disease From Simple Traits, to Complex Traits, to Personalized Medicine Preface The science of genetics began in 1900 with the independent rediscovery of Mendel's 1866 paper by Carl Correns and Hugo de Vries. Until the middle of the nineteenth century, blending theories of inheritance prevailed, but it became clear to Charles Darwin and his cousin Francis Galton that the hereditary elements must be particulate to provide the kind of variation upon which natural selection could work. Each of them proposed a particulate theory of inheritance, but the particles had to be hypothetical as the architecture of the cell and its different components were only beginning to reveal themselves to the curious eye. By 1900, a great deal was known about cell structure. In particular, chromosomes had been identified and Walther Flemming, a German scientist, had characterized their behavior in cell division (mitosis). Another German scientist, Theodor Boveri, provided evidence that chromosomes of the germ cell lineage provided continuity between generations. And in 1902, an American graduate student, Walter Sutton, connected chromosomes with genes, in a classic paper. Thomas Hunt Morgan and his associates obtained experimental proof of the chromosome theory using the fruit fly Drosophila as a model. Working with Drosophila in his Fly Room at Columbia University, Morgan and his colleagues would elucidate many of the most important principles of Mendelian genetics. In England, William Bateson became Mendel's great advocate. One would have thought such advocacy unnecessary except that, just about the time of Mendel's rediscovery, Francis Galton had come up with a model of inheritance, which he called his Ancestral Theory. Particularly in Great Britain, there was much controversy in the first decade of the twentieth century between Galton's supporters and Bateson. The Mendelians finally won out. In the course of these heated exchanges, Bateson became aware of the work of an English doctor, Archibald Garrod. Garrod was studying a disease called alkaptoneuria that caused the urine to blacken. His results suggested to Bateson that a recessive gene mutation might be involved. Bateson entered into a correspondence with Garrod, who in 1902 published a paper titled "The Incidence of Alkaptoneuria: A Study in Chemical Individuality." And with that paper, Garrod made the first connection between a human disease and a gene. The aim of this book is to provide an overview of the relationship between genes and disease, what can be done about these diseases, and the prospects for the future as we enter the era of personalized medicine. The first three chapters deal with diseases that are simple in the sense that they result because of single gene mutations. Chapter 1, "Hunting for disease genes," considers the pedigree and its use in deciphering human genetic diseases and, at the end, the question of how many genetic diseases there are in the context of the structure of the human genome and the genes it contains. Chapter 2, "How genetic diseases arise," is about how the process of mutation gives rise to genetic defects, but also about how this same process has produced millions of tiny genomic changes called single nucleotide polymorphisms (SNPs). Most SNPs have little or no effect on the individual, but they are of major importance to those who desire to investigate genetic diseases, particularly complex ones. People with and without a genetic disease can be compared to see if any of these SNPs can be associated with specific diseases. The chapter also considers what happens when mistakes occur in partitioning chromosomes properly to sperm and eggs. Chapter 3, "Ethnicity and genetic disease," examines the reasons why some diseases are more prevalent in some races and ethnic groups than others and explains why this has nothing to do with race or ethnicity per se. The second group of three chapters considers genetically complex diseases. Chapter 4, "Susceptibility genes and risk factors," is about genetic risk factors and diseases like type 2 diabetes, coronary disease, and asthma, where the environment also plays an important role. In each case, there are single gene mutations that can cause the disease. These disease mutations are considered in some detail as they show how certain single gene changes can lead to complex diseases. However, people with these single gene changes only represent a small fraction of those suffering from the disease. In most people who suffer from asthma, have type 2 diabetes, or are susceptible to coronary disease, there is a complex interplay between a variety of genetic risk factors and the environment. Unraveling these interactions is a work in progress. Chapter 5, "Genes and cancer," discusses cancer, a large collection of different genetic diseases. What they all have in common is the propensity for uncontrolled growth. It has only been possible to work out the many different genetic pathways that lead to cancer because of basic research in cell biology. This has provided the necessary background information on how the normal pathways themselves are organized. The topic of cancer genetics is so vast that select examples have been chosen to illustrate several different points concerning the disease. For example, cervical cancer shows how viruses sometimes act as causative agents of cancer. The greatly increased frequency of lung cancer in recent years illustrates that decades can elapse between the exposure of a tissue or organ to carcinogens, in this case those present in cigarette smoke, and the appearance of the disease. Like type 2 diabetes or coronary disease, schizophrenia and bipolar disease are genetically complex, as discussed in Chapter 6, "Genes and behavior." There have been many false alarms in identifying susceptibility genes for these and other behavioral conditionsthe gay gene controversy comes to mind. But there have also been some notable successes. The chapter begins by recounting the history of the "warrior gene." This odd gene has been implicated in a wide variety of bad or risk-taking behaviors. Chapter 7, "Genes and IQ: an unfinished story," deals with a subject whose relevance may not seem apparent initially. The reader may rightly ask what on earth this topic has to do with disease. The answer is that not only do quite a number of genetic diseases affect IQ, but in the first half of the last century, the presumption that "feeblemindedness" was inherited was the basis for involuntary sterilizations, particularly of women, in many states in the United States, Scandinavia, and Nazi Germany. To this day, there are those who argue that IQ differences between races and classes are largely genetic in nature and, therefore, explain certain alleged inferiorities. For better or worse, it seems likely that IQ and related tests will be used to measure intelligence for a long time because they yield numbers and numbers are easier for most people to deal with than descriptions. Take wine, for instance. All that business about tasting like black cherries with a hint of cinnamon loses out to Robert Parker's numbering system. However, his scale is so compressed, between the high 80s and 100, that a Bordeaux wine that rates 96 can command a far greater price than one that Parker grades as 90. IQ scores, in contrast, are not compressed and follow the pleasing shape of the bell curve. Furthermore, IQ does measure something that relates to what we would call intelligence. Most would agree that the cognitive powers of children with Down syndrome are qualitatively different from those of ordinary child