It is said that "necessity is the mother of invention". To be sure, wheels and pulleys were invented out of necessity by the tenacious minds of upright citi zens. Looking at the history of mankind, however, one has to add that "Ieisure is the mother of cultural improvement". Man's creative genius flourished only when his mind, freed from the worry of daily toils, was permitted to entertain apparently useless thoughts. In the same manner, one might say with regard to evolution that "natural selection mere(y tnodifted, while redundanry created". Natural selection has been extremely effective in policing alleHe mutations which arise in already existing gene loci. Because of natural selection, organisms have been able to adapt to changing environments, and by adaptive radiation many new species were created from a common ancestral form. Y et, being an effective policeman, natural selection is extremely conservative by nature. Had evolution been entirely dependent upon natural selection, from a bacterium only numerous forms of bacteria would have emerged. The creation of metazoans, vertebrates and finally mammals from unicellular organisms would have been quite impos sible, for such big leaps in evolution required the creation of new gene loci with previously nonexistent functions. Only the cistron which became redun dant was able to escape from the relentless pressure of natural selection, and by escaping, it accumulated formerly forbidden mutations to emerge as a new gene locus.

Gene duplication has long been believed to have played a major role in the rise of biological novelty through evolution of new function and gene expression patterns. The first book to examine gene duplication across all levels of biological organization, Evolution after Gene Duplication presents a comprehensive picture of the mechanistic process by which gene duplication may have played a role in generating biodiversity. Key Features: Explores comparative genomics, genome evolution studies and analysis of multi-gene families such as Hox, globins, olfactory receptors and MHC (immune system) A complete post-genome treatment of the topic originally covered by Ohno's 1970 classic, this volume extends coverage to include the fate of associated regulatory pathways Taps the significant increase in multi-gene family data that has resulted from comparative genomics Comprehensive coverage that includes opposing theoretical viewpoints, comparative genomics data, theoretical and empirical evidence and the role of bioinformatics in the study of gene duplication This up-to-date overview of theory and mathematical models along with practical examples is suitable for scientists across various levels of biology as well as instructors and graduate students.

Although interest in evolutionary novelties can be that these different mechanisms cooperate in the mak traced back to the time of Darwin, the appreciation ing of new genes. In the second phase of new gene evolution, conventional models of new gene evolution, and systematical experimental pursuit of the origin and evolution of new gene functions did not appear for example by gene duplication, held that the muta until the early years of last decade. Since the 1970s, tions fixed in the early stages of the new genes are Susumu Ohno, Walter Gilbert, and others from the assumed to be neutral or nearly neutral. However, it area of evolutionary genetics have made pioneer ef appears that the force of Darwinian positive selection has been detectably strong from the outset in avail forts to elaborate possibilities for major biological mechanisms, for example, gene duplication and exon able population genetic studies of young genes created through the process of exon recombination. This may shuffling, by which new gene functions could arise. However, the problem of new gene evolution did not account for a common phenomenon in phylogenetic catch significant attention among biologists generally analyses of genes with changed functions: the early even recently. One of the reasons was the lack of ex stages of such genes are usually associated with accel perimental or observational systems for investigating erated substitution rates. Nonetheless, a more general factual details of the 'birth' process of new genes.

In Gene Sharing and Evolution Piatigorsky explores the generality and implications of gene sharing throughout evolution and argues that most if not all proteins perform a variety of functions in the same and in different species, and that this is a fundamental necessity for evolution.

New viral diseases are emerging continuously. Viruses adapt to new environments at astounding rates. Genetic variability of viruses jeopardizes vaccine efficacy. For many viruses mutants resistant to antiviral agents or host immune responses arise readily, for example, with HIV and influenza. These variations are all of utmost importance for human and animal health as they have prevented us from controlling these epidemic pathogens. This book focuses on the mechanisms that viruses use to evolve, survive and cause disease in their hosts. Covering human, animal, plant and bacterial viruses, it provides both the basic foundations for the evolutionary dynamics of viruses and specific examples of emerging diseases. - NEW - methods to establish relationships among viruses and the mechanisms that affect virus evolution - UNIQUE - combines theoretical concepts in evolution with detailed analyses of the evolution of important virus groups - SPECIFIC - Bacterial, plant, animal and human viruses are compared regarding their interation with their hosts

Sequence - Evolution - Function is an introduction to the computational approaches that play a critical role in the emerging new branch of biology known as functional genomics. The book provides the reader with an understanding of the principles and approaches of functional genomics and of the potential and limitations of computational and experimental approaches to genome analysis. Sequence - Evolution - Function should help bridge the "digital divide" between biologists and computer scientists, allowing biologists to better grasp the peculiarities of the emerging field of Genome Biology and to learn how to benefit from the enormous amount of sequence data available in the public databases. The book is non-technical with respect to the computer methods for genome analysis and discusses these methods from the user's viewpoint, without addressing mathematical and algorithmic details. Prior practical familiarity with the basic methods for sequence analysis is a major advantage, but a reader without such experience will be able to use the book as an introduction to these methods. This book is perfect for introductory level courses in computational methods for comparative and functional genomics.

The Arthur M. Sackler Colloquia of the National Academy of Sciences address scientific topics of broad and current interest, cutting across the boundaries of traditional disciplines. Each year, four or five such colloquia are scheduled, typically two days in length and international in scope. Colloquia are organized by a member of the Academy, often with the assistance of an organizing committee, and feature presentations by leading scientists in the field and discussions with a hundred or more researchers with an interest in the topic. Colloquia presentations are recorded and posted on the National Academy of Sciences Sackler colloquia website and published on CD-ROM. These Colloquia are made possible by a generous gift from Mrs. Jill Sackler, in memory of her husband, Arthur M. Sackler.