Microbial Evolution


Book Description

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.




Genomics and Evolution of Microbial Eukaryotes


Book Description

Genomics and Evolution of Eukaryotic Microbes synthesizes the rapidly emerging fields of eukaryotic diversity and genome evolution. Eukaryotes (cells with nuclei) evolved as microbes and have existed on Earth for approximately two billion years. The tremendous diversity of eukaryotic microbes (protists) is often overlooked by those who study the macroscopic eukaryotic lineages: plants, animals, and fungi. Yet, eukaryotic microbes are of critical importance to ecosystems, human health, and our desire to understand biodiversity on Earth. By bringing together groundbreaking data from genome studies of diverse eukaryotic microbes, this book elucidates the many novelties among eukaryotic genomes and provides a single resource for otherwise widely dispersed information. Eukaryotic microorganisms impact both our health and our environment. These organisms include some of the deadliest known pathogens such as Plasmodium falciparum, a causative agent of malaria, and Entamoeba histolytica an agent of dysentery. Eukaryotic microbes also play a significant role in environments through their involvement in global biogeochemical cycles. Such roles are perhaps best exemplified by the coccolithophores, including the species Emiliania huxleyi, which can create 'blooms' in the oceans that are visible from outer space (i.e. as large as the state of Alaska). Despite the great importance and breadth of eukaryotic microbes (the vast majority of major ukaryotic lineages are microbial, with plants, animals and fungi representing just three of an estimated 60-200 major lineages), our understanding of their diversity and phylogeny is only now rapidly expanding, in part bolstered by genomic studies. This book presents analyses and interpretations from experts in the field. Recent advances, particularly in DNA sequencing technologies, have made eukaryotic microbes more accessible to genome analyses. Unravelling the wealth of information on eukaryotic genomes will invariably revolutionize our understanding of eukaryotes, including their physiology, systematics, and ecology.




The Logic of Chance


Book Description

The Logic of Chance offers a reappraisal and a new synthesis of theories, concepts, and hypotheses on the key aspects of the evolution of life on earth in light of comparative genomics and systems biology. The author presents many specific examples from systems and comparative genomic analysis to begin to build a new, much more detailed, complex, and realistic picture of evolution. The book examines a broad range of topics in evolutionary biology including the inadequacy of natural selection and adaptation as the only or even the main mode of evolution; the key role of horizontal gene transfer in evolution and the consequent overhaul of the Tree of Life concept; the central, underappreciated evolutionary importance of viruses; the origin of eukaryotes as a result of endosymbiosis; the concomitant origin of cells and viruses on the primordial earth; universal dependences between genomic and molecular-phenomic variables; and the evolving landscape of constraints that shape the evolution of genomes and molecular phenomes. "Koonin's account of viral and pre-eukaryotic evolution is undoubtedly up-to-date. His "mega views" of evolution (given what was said above) and his cosmological musings, on the other hand, are interesting reading." Summing Up: Recommended Reprinted with permission from CHOICE, copyright by the American Library Association.




The Pangenome


Book Description

This open access book offers the first comprehensive account of the pan-genome concept and its manifold implications. The realization that the genetic repertoire of a biological species always encompasses more than the genome of each individual is one of the earliest examples of big data in biology that opened biology to the unbounded. The study of genetic variation observed within a species challenges existing views and has profound consequences for our understanding of the fundamental mechanisms underpinning bacterial biology and evolution. The underlying rationale extends well beyond the initial prokaryotic focus to all kingdoms of life and evolves into similar concepts for metagenomes, phenomes and epigenomes. The book’s respective chapters address a range of topics, from the serendipitous emergence of the pan-genome concept and its impacts on the fields of microbiology, vaccinology and antimicrobial resistance, to the study of microbial communities, bioinformatic applications and mathematical models that tie in with complex systems and economic theory. Given its scope, the book will appeal to a broad readership interested in population dynamics, evolutionary biology and genomics.




The New Science of Metagenomics


Book Description

Although we can't usually see them, microbes are essential for every part of human life-indeed all life on Earth. The emerging field of metagenomics offers a new way of exploring the microbial world that will transform modern microbiology and lead to practical applications in medicine, agriculture, alternative energy, environmental remediation, and many others areas. Metagenomics allows researchers to look at the genomes of all of the microbes in an environment at once, providing a "meta" view of the whole microbial community and the complex interactions within it. It's a quantum leap beyond traditional research techniques that rely on studying-one at a time-the few microbes that can be grown in the laboratory. At the request of the National Science Foundation, five Institutes of the National Institutes of Health, and the Department of Energy, the National Research Council organized a committee to address the current state of metagenomics and identify obstacles current researchers are facing in order to determine how to best support the field and encourage its success. The New Science of Metagenomics recommends the establishment of a "Global Metagenomics Initiative" comprising a small number of large-scale metagenomics projects as well as many medium- and small-scale projects to advance the technology and develop the standard practices needed to advance the field. The report also addresses database needs, methodological challenges, and the importance of interdisciplinary collaboration in supporting this new field.




Microbial Functional Genomics


Book Description

Microbial Functional Genomics offers a timely summary of the principles, approaches, and applications. It presents a comprehensive review of microbial functional genomics, covering microbial diversity, microbial genome sequencing, genomic technologies, genome-wide functional analysis, applied functional genomics, and future directions. An introduction will offer a definition of the field and an overview of the historical and comparative genomics aspects.




Introduction to Evolutionary Genomics


Book Description

This book is the first of its kind to explain the fundamentals of evolutionary genomics. The comprehensive coverage includes concise descriptions of a variety of genome organizations, a thorough discussion of the methods used, and a detailed review of genome sequence processing procedures. The opening chapters also provide the necessary basics for readers unfamiliar with evolutionary studies. Features: introduces the basics of molecular biology, DNA replication, mutation, phylogeny, neutral evolution, and natural selection; presents a brief evolutionary history of life from the primordial seas to the emergence of humans; describes the genomes of prokaryotes, eukaryotes, vertebrates, and humans; reviews methods for genome sequencing, phenotype data collection, homology searches and analysis, and phylogenetic tree and network building; discusses databases of genome sequences and related information, evolutionary distances, and population genomics; provides supplementary material at an associated website.




Prokaryotic Cytoskeletons


Book Description

This book describes the structures and functions of active protein filaments, found in bacteria and archaea, and now known to perform crucial roles in cell division and intra-cellular motility, as well as being essential for controlling cell shape and growth. These roles are possible because the cytoskeletal and cytomotive filaments provide long range order from small subunits. Studies of these filaments are therefore of central importance to understanding prokaryotic cell biology. The wide variation in subunit and polymer structure and its relationship with the range of functions also provide important insights into cell evolution, including the emergence of eukaryotic cells. Individual chapters, written by leading researchers, review the great advances made in the past 20-25 years, and still ongoing, to discover the architectures, dynamics and roles of filaments found in relevant model organisms. Others describe one of the families of dynamic filaments found in many species. The most common types of filament are deeply related to eukaryotic cytoskeletal proteins, notably actin and tubulin that polymerise and depolymerise under the control of nucleotide hydrolysis. Related systems are found to perform a variety of roles, depending on the organisms. Surprisingly, prokaryotes all lack the molecular motors associated with eukaryotic F-actin and microtubules. Archaea, but not bacteria, also have active filaments related to the eukaryotic ESCRT system. Non-dynamic fibres, including intermediate filament-like structures, are known to occur in some bacteria.. Details of known filament structures are discussed and related to what has been established about their molecular mechanisms, including current controversies. The final chapter covers the use of some of these dynamic filaments in Systems Biology research. The level of information in all chapters is suitable both for active researchers and for advanced students in courses involving bacterial or archaeal physiology, molecular microbiology, structural cell biology, molecular motility or evolution. Chapter 3 of this book is open access under a CC BY 4.0 license.




Genomics and Evolution of Microbial Eukaryotes


Book Description

This book represents a unique combination of recently-emerged information on eukaryotic microbes, evolution and genomics. Eukaryotes, cells with nuclei, evolved as microbes and have existed on Earth for approximately 2 billion years. Although currently relatively understudied, eukaryotic microorganisms are of critical importance to ecosystems (through their involvement in global biogeochemical cycles), human health (they include some of the deadliest pathogens), and our desire tounderstand global biodiversity. Recent advances, particularly in DNA sequencing technologies, are making eukaryotic microbes more accessible through genome analyses. Insights from these studies are challenging previously held theories of genome evolution, based on studies of a limited number of plants,animals and fungi.




Evolutionary Feedbacks Between Population Biology and Genome Architecture


Book Description

This eBook presents all 10 articles published under the Frontiers Research Topic "Evolutionary Feedbacks Between Population Biology and Genome Architecture", edited by Scott V. Edwards and Tariq Ezaz. With the rise of rapid genome sequencing across the Tree of Life, challenges arise in understanding the major evolutionary forces influencing the structure of microbial and eukaryotic genomes, in particular the prevalence of natural selection versus genetic drift in shaping those genomes. Additional complexities in understanding genome architecture arise with the increasing incidence of interspecific hybridization as a force for shaping genotypes and phenotypes. A key paradigm shift facilitating a more nuanced interpretation of genomes came with the rise of the nearly neutral theory in the 1970s, followed by a greater appreciation for the contribution of nonadaptive forces such as genetic drift to genome structure in the 1990s and 2000s. The articles published in this eBook grapple with these issues and provide an update as to the ways in which modern population genetics and genome informatics deepen our understanding of the subtle interplay between these myriad forces. From intraspecific to macroevolutionary studies, population biology and population genetics are now major tools for understanding the broad landscape of how genomes evolve across the Tree of Life. This volume is a celebration across diverse taxa of the contributions of population genetics thinking to genome studies. We hope it spurs additional research and clarity in the ongoing search for rules governing the evolution of genomes.