Download or read book Mechanism of Rapid Adaptation Under Selection written by Emiko Beatriz Sano and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-dependent accumulation of mutants in several genetic systems has led to the controversial conclusion that bacteria possess a mechanism to elevate general mutagenesis in response to stress. In particular, extensive study of the Cairns system has kept the controversy alive despite theoretical analysis suggesting that general mutagenesis is counter-productive. In the Cairns system, a lac mutant strain gives rise to Lac revertant colonies that accumulate above a non-growing lawn over a week. Two conflicting models explain this behavior. The Stress-Induced Mutagenesis model proposes that cells have a mechanism that creates genome-wide mutations during growth limitation that may relieve the stress. Most mutations are attributed to action of the error-prone Pol IV polymerase during recombination-dependent double-stranded break repair in non-growing cells. We have directly tested this model by measuring mutation rates during non-selective growth (the only condition under which a true mutation rate can be measured). Cell functions that are proposed to change in response to stress (SOS, Pol IV and recombination) and cause mutagenesis are given or removed from growing cultures. We find that none of these factors affect mutation rate in growing cells. In addition, we find that vast (non-physiological) over-expression of Pol IV causes mutagenesis that shows no dependence on recombination. Results are conflicting with predictions of the Stress-Induced Mutagenesis model. Results are explained by the alternative Growth-Under-Selection model in which pre-existing small-effect mutations initiate slow-growing clones under selection. Within developing colonies, secondary genetic improvements occur without enhanced mutagenesis. These mutations are made more likely by the increasing number of potential targets for mutations within a growing colony. We provide evidence that revertant colonies appearing under selection are initiated by pre-existing cells with an amplification of the mutant lacgene. By killing these pre-existing cells, we prevent appearance of revertant colonies on selective plates. This demonstrates that revertant number is determined before selection cannot be created in response to stress.
Download or read book Genetics of Adaptation written by Rodney Mauricio and published by Springer Science & Business Media. This book was released on 2005-07-20 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: An enduring controversy in evolutionary biology is the genetic basis of adaptation. Darwin emphasized "many slight differences" as the ultimate source of variation to be acted upon by natural selection. In the early 1900’s, this view was opposed by "Mendelian geneticists", who emphasized the importance of "macromutations" in evolution. The Modern Synthesis resolved this controversy, concluding that mutations in genes of very small effect were responsible for adaptive evolution. A decade ago, Allen Orr and Jerry Coyne reexamined the evidence for this neo-Darwinian view and found that both the theoretical and empirical basis for it were weak. Orr and Coyne encouraged evolutionary biologists to reexamine this neglected question: what is the genetic basis of adaptive evolution? In this volume, a new generation of biologists have taken up this challenge. Using advances in both molecular genetic and statistical techniques, evolutionary geneticists have made considerable progress in this emerging field. In this volume, a diversity of examples from plant and animal studies provides valuable information for those interested in the genetics and evolution of complex traits.
Download or read book In the Light of Evolution written by National Academy of Sciences and published by . This book was released on 2007 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Adaptation and Natural Selection written by George Christopher Williams and published by Princeton University Press. This book was released on 2018-10-30 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological evolution is a fact—but the many conflicting theories of evolution remain controversial even today. When Adaptation and Natural Selection was first published in 1966, it struck a powerful blow against those who argued for the concept of group selection—the idea that evolution acts to select entire species rather than individuals. Williams’s famous work in favor of simple Darwinism over group selection has become a classic of science literature, valued for its thorough and convincing argument and its relevance to many fields outside of biology. Now with a new foreword by Richard Dawkins, Adaptation and Natural Selection is an essential text for understanding the nature of scientific debate.
Download or read book Statistical Population Genomics written by Julien Y Dutheil and published by . This book was released on 2020-10-08 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access volume presents state-of-the-art inference methods in population genomics, focusing on data analysis based on rigorous statistical techniques. After introducing general concepts related to the biology of genomes and their evolution, the book covers state-of-the-art methods for the analysis of genomes in populations, including demography inference, population structure analysis and detection of selection, using both model-based inference and simulation procedures. Last but not least, it offers an overview of the current knowledge acquired by applying such methods to a large variety of eukaryotic organisms. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, pointers to the relevant literature, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Statistical Population Genomics aims to promote and ensure successful applications of population genomic methods to an increasing number of model systems and biological questions. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.
Download or read book Yeast Sugar Metabolism written by Friedrich K. Zimmermann and published by CRC Press. This book was released on 1997-03-10 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yeast Sugar Metabolism looks at the biomechanics, genetics, biotechnology and applications of yeast sugar. The yeast Saccharomyces cereisiae has played a central role in the evolution of microbiology biochemistry and genetics, in addition to its use of a technical microbe for the production of alcoholic beverages and leavening of dough.
Download or read book The Evolution of Population Biology written by Rama S. Singh and published by Cambridge University Press. This book was released on 2004-01-15 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 2004 collection of essays deals with the foundation and historical development of population biology and its relationship to population genetics and population ecology on the one hand and to the rapidly growing fields of molecular quantitative genetics, genomics and bioinformatics on the other. Such an interdisciplinary treatment of population biology has never been attempted before. The volume is set in a historical context, but it has an up-to-date coverage of material in various related fields. The areas covered are the foundation of population biology, life history evolution and demography, density and frequency dependent selection, recent advances in quantitative genetics and bioinformatics, evolutionary case history of model organisms focusing on polymorphisms and selection, mating system evolution and evolution in the hybrid zones, and applied population biology including conservation, infectious diseases and human diversity. This is the third of three volumes published in honour of Richard Lewontin.
Download or read book Stress Induced Mutagenesis written by David Mittelman and published by Springer Science & Business Media. This book was released on 2013-03-12 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery of stress-induced mutagenesis has changed ideas about mutation and evolution, and revealed mutagenic programs that differ from standard spontaneous mutagenesis in rapidly proliferating cells. The stress-induced mutations occur during growth-limiting stress, and can include adaptive mutations that allow growth in the otherwise growth-limiting environment. The stress responses increase mutagenesis specifically when cells are maladapted to their environments, i.e. are stressed, potentially accelerating evolution then. The mutation mechanism also includes temporary suspension of post-synthesis mismatch repair, resembling mutagenesis characteristic of some cancers. Stress-induced mutation mechanisms may provide important models for genome instability underlying some cancers and genetic diseases, resistance to chemotherapeutic and antibiotic drugs, pathogenicity of microbes, and many other important evolutionary processes. This book covers pathways of stress-induced mutagenesis in all systems. The principle focus is mammalian systems, but much of what is known of these pathways comes from non-mammalian systems.
Download or read book The Tree Sparrow written by J. Denis Summers-Smith and published by . This book was released on 1995 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tree Sparrows are distributed throughout most of Europe and Asia, and have been introduced in many other parts of the world. This book describes the species' origins and early spread, as well as a speculative section on the evolution of the distribution. It discusses the species' habits, breeding, movements, numbers and food.
Download or read book The Gene Ontology Handbook written by Christophe Dessimoz and published by . This book was released on 2020-10-08 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a practical and self-contained overview of the Gene Ontology (GO), the leading project to organize biological knowledge on genes and their products across genomic resources. Written for biologists and bioinformaticians, it covers the state-of-the-art of how GO annotations are made, how they are evaluated, and what sort of analyses can and cannot be done with the GO. In the spirit of the Methods in Molecular Biology book series, there is an emphasis throughout the chapters on providing practical guidance and troubleshooting advice. Authoritative and accessible, The Gene Ontology Handbook serves non-experts as well as seasoned GO users as a thorough guide to this powerful knowledge system. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.
Download or read book Microbial Evolution written by Howard Ochman and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bacteria have been the dominant forms of life on Earth for the past 3.5 billion years. They rapidly evolve, constantly changing their genetic architecture through horizontal DNA transfer and other mechanisms. Consequently, it can be difficult to define individual species and determine how they are related. Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology examines how bacteria and other microbes evolve, focusing on insights from genomics-based studies. Contributors discuss the origins of new microbial populations, the evolutionary and ecological mechanisms that keep species separate once they have diverged, and the challenges of constructing phylogenetic trees that accurately reflect their relationships. They describe the organization of microbial genomes, the various mutations that occur, including the birth of new genes de novo and by duplication, and how natural selection acts on those changes. The role of horizontal gene transfer as a strong driver of microbial evolution is emphasized throughout. The authors also explore the geologic evidence for early microbial evolution and describe the use of microbial evolution experiments to examine phenomena like natural selection. This volume will thus be essential reading for all microbial ecologists, population geneticists, and evolutionary biologists.
Download or read book Mechanisms of Adaptation written by J.R. Spkatch and published by Elsevier. This book was released on 2014-04-24 with total page 615 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bacteria: Volume VII: Mechanisms of Adaptation explores the mechanisms of bacterial adaptations and covers topics ranging from bacterial spores, cysts, and stalks to nitrogen fixation, bacterial chemotaxis, bacteriophage growth, and the structure and biosynthesis of bacterial cell walls. The roles of appendages and surface layers in adaptation of bacteria to their environment are also considered, along with cell division in Escherichia coli. This volume is comprised of nine chapters and begins with a discussion on the structure, properties, formation, and regulation of spores, cysts, and stalks in actinomycetes, blue-green bacteria, myxobacteria, Bacillus, Azotobacter, and Caulobacter. The reader is then introduced to the biochemistry, regulation, genetics, and evolution of nitrogen fixing in organisms; the receptors involved in bacterial chemotaxis and the nature of the sensing mechanism; the outer membrane of gram-negative bacteria; and bacterial functions involved in nutrient detection and acquisition. The roles played by organelles and surface layers in the adaptation of bacteria to their environment are also examined. The final chapter deals with the regulation of, and coordination between, the multitude of events involved in cell division in Escherichia coli. This monograph will be a useful resource for microbiologists, bacteriologists, biochemists, and biologists.
Download or read book Webvision written by Helga Kolb and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mathematical Population Genetics 1 written by Warren J. Ewens and published by Springer Science & Business Media. This book was released on 2012-10-01 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first of a planned two-volume work discussing the mathematical aspects of population genetics with an emphasis on evolutionary theory. This volume draws heavily from the author’s 1979 classic, but it has been revised and expanded to include recent topics which follow naturally from the treatment in the earlier edition, such as the theory of molecular population genetics.
Download or read book Evolution s Wedge written by David Pfennig and published by Univ of California Press. This book was released on 2012-10-25 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evolutionary biology has long sought to explain how new traits and new species arise. Darwin maintained that competition is key to understanding this biodiversity and held that selection acting to minimize competition causes competitors to become increasingly different, thereby promoting new traits and new species. Despite Darwin’s emphasis, competition’s role in diversification remains controversial and largely underappreciated. In their synthetic and provocative book, evolutionary ecologists David and Karin Pfennig explore competition's role in generating and maintaining biodiversity. The authors discuss how selection can lessen resource competition or costly reproductive interactions by promoting trait evolution through a process known as character displacement. They further describe character displacement’s underlying genetic and developmental mechanisms. The authors then consider character displacement’s myriad downstream effects, ranging from shaping ecological communities to promoting new traits and new species and even fueling large-scale evolutionary trends. Drawing on numerous studies from natural populations, and written for a broad audience, Evolution’s Wedge seeks to inspire future research into character displacement’s many implications for ecology and evolution.
Download or read book The Making of the Fittest DNA and the Ultimate Forensic Record of Evolution written by Sean B. Carroll and published by W. W. Norton & Company. This book was released on 2007-08-28 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: A geneticist discusses the role of DNA in the evolution of life on Earth, explaining how an analysis of DNA reveals a complete record of the events that have shaped each species and how it provides evidence of the validity of the theory of evolution.
Download or read book Extended Heredity written by Russell Bonduriansky and published by Princeton University Press. This book was released on 2020-04-14 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bonduriansky and Day challenge the premise that genes alone mediate the transmission of biological information across generations and provide the raw material for natural selection. They explore the latest research showing that what happens during our lifetimes—and even our parents’ and grandparents’ lifetimes—can influence the features of our descendants. Based on this evidence, Bonduriansky and Day develop an extended concept of heredity that upends ideas about how traits can and cannot be transmitted across generations, opening the door to a new understanding of inheritance, evolution, and even human health. --Adapted from publisher description.
