Biology

Aging has long since been ascribed to the gradual accumulation of DNA mutations in the genome of somatic cells. However, it is only recently that the necessary sophisticated technology has been developed to begin testing this theory and its consequences. This book critically reviews the concept of genomic instability as a possible universal cause of aging in the context of a new, holistic understanding of genome functioning in complex organisms resulting from recent advances in functional genomics and systems biology. It provides a synthesis of current research, as well as a look ahead to the design of strategies to retard or reverse the deleterious effects of aging. This is particularly important in a time when we are urgently trying to unravel the genetic component of aging-related diseases. Moreover, there is a growing public recognition of the imperative of understanding more about the underlying biology of aging, driven by continuing demographic change.

Ancestral sequence reconstruction is a technique of growing importance in molecular evolutionary biology and comparative genomics. As a powerful tool for testing evolutionary and ecological hypotheses, as well as uncovering the link between sequence and molecular phenotype, there are potential applications in almost all fields of applied molecular biology. This book starts with a historical overview of the field, before discussing the potential applications in drug discovery and the pharmaceutical industry. This is followed by a section on computational methodology, which provides a detailed discussion of the available methods for reconstructing ancestral sequences (including their advantages, disadvantages, and potential pitfalls). Purely computational applications of the technique are then covered, including whole proteome reconstruction. Further chapters provide a detailed discussion on taking computationally reconstructed sequences and synthesizing them in the laboratory. The book concludes with a description of the scientific questions where experimental ancestral sequence reconstruction has been utilized to provide insights and inform future research.

Animal life, now and over the past half billion years, is incredibly diverse. Describing and understanding the evolution of this diversity of body plans — from vertebrates such as humans and fish to the numerous invertebrate groups including sponges, insects, molluscs, and the many groups of worms — is a major goal of evolutionary biology. This book adopts a modern, integrated approach to describe how current molecular genetic techniques and disciplines as diverse as palaeontology, embryology, and genomics have been combined, resulting in a dramatic renaissance in the study of animal evolution. The last decade has seen growing interest in evolutionary biology fuelled by a wealth of data from molecular biology. Modern phylogenies integrating evidence from molecules, embryological data, and morphology of living and fossil taxa provide a wide consensus of the major branching patterns of the tree of life; moreover, the links between phenotype and genotype are increasingly well understood. This has resulted in a reliable tree of relationships that has been widely accepted and has spawned numerous new and exciting questions that require a reassessment of the origins and radiation of animal life. The focus of this volume is at the level of major animal groups, the morphological innovations that define them, and the mechanisms of change to their embryology that have resulted in their evolution. Current research themes and future prospects are highlighted including phylogeny reconstruction, comparative developmental biology, the value of different sources of data and the importance of fossils, homology assessment, character evolution, phylogeny of major groups of animals, and genome evolution. These topics are integrated in the light of a 'new animal phylogeny', to provide fresh insights into the patterns and processes of animal evolution.

The role of genes in governing behavior remains one of the most controversial topics in human biology. Early in this century, over-eager promotion of a genetic basis for behavior led to the excesses, and ultimately the horrors, of eugenics. Subsequent reactions to these excesses, both within the scientific community and society as a whole, led to a nearly complete dismissal of a role for genes in human behavior. Slowly we come back to a more balanced view. Detailed studies of the biological basis of behavior in animals, from the simplest single-celled creatures through the most complex mammals, show that genes play an important role in guiding behavior. Studies in humans, especially those involving twins reared together or apart, indicate clearly that humans are no exception. The variability we see around us in the way humans respond in a given situation is strongly influenced by the variability in their genetic makeup. So are we powerless creations of our genes? Not at all. Guided by differing genetic makeups, we respond to our environment in different ways. But these responses, and the actions of our genes, are in turn modified by the environment itself. Behavior is the result of a balancing act between genes and the environment; between what we inherit and what we learn. To understand ourselves fully, we must understand both.

About 99.9% of vertebrate species reproduce sexually. This makes the exceptional 0.1%—the asexual or clonal reproducers—fascinating in their own right, and also uniquely instructive about the biological significance of alternative reproductive modes. This book describes the genetics, ecology, natural history, and evolution of all of the world's approximately 100 “species” of vertebrate animal that routinely display one form or another of clonal or quasi-clonal reproduction. The book investigates the astounding realm of sexual abstinence, from the levels of DNA molecules and somatic cells to whole animals and natural populations. Also described is how scientists have learned to mimic and extend nature's own clonal processes by engineering perfect copies of genes, genomes, and whole animals in the laboratory. By considering the many facets of sexual abstinence and clonal reproduction in vertebrate animals, new light is also shed on the biological meaning and ramifications of standard sexuality.

The field of molecular evolution has experienced explosive growth in recent years due to the rapid accumulation of genetic sequence data, continuous improvements to computer hardware and software, and the development of sophisticated analytical methods. The increasing availability of large genomic data sets requires powerful statistical methods to analyse and interpret them, generating both computational and conceptual challenges for the field. This book provides a comprehensive coverage of modern statistical and computational methods used in molecular evolutionary analysis, such as maximum likelihood and Bayesian statistics. It describes the models, methods and algorithms that are most useful for analysing the ever-increasing supply of molecular sequence data, with a view to furthering our understanding of the evolution of genes and genomes. The book emphasizes essential concepts rather than mathematical proofs. It includes detailed derivations and implementation details, as well as numerous illustrations, worked examples, and exercises.

This book explains the history and strategy of the intelligent design creationist movement, which is headquartered at the Discovery Institute’s Center for Science and Culture in Seattle, WA. The movement’s twenty-year “Wedge Strategy,” implementation of which began in 1998, is aimed at bringing intelligent design into American public schools, public policymaking, and the cultural mainstream. Beginning with a brief history of the movement and the authentication of the “Wedge Document,” in which the Wedge Strategy is outlined, the book critiques the incompetent science and rhetorical tactics of the movement’s leaders: Douglas Axe, Paul Chien, Jonathan Wells, Michael Behe, and William Dembski. The movement’s own documents reveal its religious funding sources and its execution of all phases of the strategy except the production of genuine scientific data, including its development of a legal defense against challenges to the teaching of intelligent design. The book recounts the movement’s political maneuvering in its effort to influence science curricula in individual states, most notably Kansas and Ohio, and to develop political support among members of Congress. Importantly, the book documents the centrality of religion to intelligent design, its leaders’ associations with Christian extremists, its continuity with earlier forms of creationism, and its ambitions for academic legitimacy. This 2007 edition provides updates on the movement’s efforts in Kansas and Ohio and offers a firsthand account by Barbara Forrest, who was an expert witness for the plaintiffs, of the landmark legal case involving intelligent design, Kitzmiller et al. v. Dover Area School District (2005).

Some six million years ago, two branches of the evolutionary tree diverged: one that led to chimpanzees and bonobos, and one that led to us. Extraordinary advances in our ability to obtain and process DNA sequence information permits scientists to address fundamental questions about the evolutionary histories of varied species, including our own. Ascertaining the sequence of the genome — the complete complement of DNA information — from both humans and chimpanzees allows scientists to address such questions as: which genes were subjected to natural selection along our evolutionary branch? Are these the genetic changes that made us human? The book addresses these and other questions about human evolutionary history, including our domestication of other animals and of plants. It also explores how researchers use the tools of molecular genetics and population genetics theory to unravel the secrets of the natural histories of genes and genomes. Much like detectives looking to ascertain the circumstances behind a crime, these scientists can develop and test inferences about the nature of the natural selection and other evolutionary pressures that have shaped the organisms that harbor these genes.

This book addresses the most paradoxical finding of recent aging research: the cessation of demographic aging. The authors show that aging stops at the level of the individual organism, and explain why evolution allows this. The implications of this counter-intuitive conclusion are profound. Aging research now needs to accept three uncomfortable truths. First, aging is not a cumulative physiological process. Second, the fundamental theory that is required to explain, manipulate, and probe the phenomena of aging comes from evolutionary biology. Third, strong-inference experimental strategies for aging must be founded in evolutionary research, not cell or molecular biology. But there are also significant consequences of this work for human aging. First, biomedical strategies that are founded on the traditional cell-molecular theories of aging are bound to fail, because their fundamental premises are incorrect. Second, the ultimate technological problem of controlling human aging is redefined by the authors as having two parts:(a) ameliorating an aging phase that can now be seen as merely transitory; and (b) achieving an earlier and healthier post-aging phase. Third, the authors propose one possibility by which both of these goals might be achieved. The outcome of fifteen years of research by the authors, this book brings together new applications of evolutionary theory, new models for demography, and massive experimentation. As hard as it is to deal scientifically with the paradoxes and complexities of aging that stops, this key finding unlocks the box containing one of the most profound mysteries of biology.

This book recreates the story of life before Homo sapiens walked the earth. It was once thought that “Peking Man”, the remains of a cave man discovered at the famous fossil site of Dragon Bone Hill in China, had been a great hunter. But Peking Man was actually a composite of the remains of some fifty women, children, and men unfortunate enough to have been the prey of a giant cave hyena. The book retells the story of the cave's unique species of early human, Homo erectus. New evidence shows that Homo erectus was an opportunist who rode a tide of environmental change out of Africa into Eurasia, puddle-jumping from one gene pool to the next. Armed with a shaky hold on fire and some sharp rocks, Homo erectus survived for over 1.5 million years, much longer than Homo sapiens, our own species, has been on Earth. Tell-tale marks on fossil bones show that the lives of these early humans were brutal, yet there are fleeting glimpses of human compassion as well. The small brain of Homo erectus and its strangely unchanging culture indicate that the species could not talk. Part of that primitive culture included ritualized aggression, to which the extremely thick skulls of Homo erectus bear witness.