How small can a free-living organism be? On the surface, this question is straightforward-in principle, the smallest cells can be identified and measured. But understanding what factors determine this lower limit, and addressing the host of other questions that follow on from this knowledge, require a fundamental understanding of the chemistry and ecology of cellular life. The recent report of evidence for life in a martian meteorite and the prospect of searching for biological signatures in intelligently chosen samples from Mars and elsewhere bring a new immediacy to such questions. How do we recognize the morphological or chemical remnants of life in rocks deposited 4 billion years ago on another planet? Are the empirical limits on cell size identified by observation on Earth applicable to life wherever it may occur, or is minimum size a function of the particular chemistry of an individual planetary surface? These questions formed the focus of a workshop on the size limits of very small organisms, organized by the Steering .Group for the Workshop on Size Limits of Very Small Microorganisms and held on October 22 and 23, 1998. Eighteen invited panelists, representing fields ranging from cell biology and molecular genetics to paleontology and mineralogy, joined with an almost equal number of other participants in a wide-ranging exploration of minimum cell size and the challenge of interpreting micro- and nano-scale features of sedimentary rocks found on Earth or elsewhere in the solar system. This document contains the proceedings of that workshop. It includes position papers presented by the individual panelists, arranged by panel, along with a summary, for each of the four sessions, of extensive roundtable discussions that involved the panelists as well as other workshop participants.

The second edition of Horizontal Gene Transfer has been organized to provide a concise and up-to-date coverage of the most important discoveries in this fascinating field. Written by the most prominent gene transfer and genome analytical scientists, this book details experimental evidence for the phenomenon of horizontal gene transfer and discusses further evidence provided by the recent completion of genomic sequences from Archea, Bacteria, and Eucarya members. The relevance of horizontal gene transfer to plant and metazoan taxonomy, GM foods, antibiotic resistance, paleontology, and phylogenetic reconstruction is also explored. Horizontal Gene Transfer is essential for microbiologists, geneticists, biochemists, evolutionary biologists, infectious disease specialists, paleontologists, ecologists, and researchers working in plant/animal systematics and agriculture with an interest in gene transfer. This includes scientific researchers from government and industry concerned with the release of genetically modified organisms. - Up-to-the-minute reviews, maps, conclusions, urls to relevant websites and colour figures - Unique chapters, for example one written by paleontologists presents data for horizontal gene transfer from fingerprints form the fossil record

Horizontal gene transfer (HGT) events encompass processes as varied as the exchange of genetic material between microbes coexisting in the same environment, between symbiotic bacteria and their eukaryotic hosts, and the evolution of organelles by symbiosis, in which whole genomes are acquired. In Horizontal Gene Transfer: Genomes in Flux, expert researchers contribute an overview of HGT concepts as well as specific case histories that highlight the most current progress to inspire future work. Divided into three sections, the volume begins with an overview of terminology, concepts and the implications of HGT on current evolutionary thought and philosophy, and continues with methods involving computer and bioinformatics analyses of genomic data as well as molecular biology techniques for identifying, quantifying, and differentiating instances of HGT. A section of case studies follows, which provides detailed accounts of how HGT has shaped evolution across the diversity of organisms and organismal lineages. As a volume of the highly successful Methods in Molecular BiologyTM series, this work provides the kind of detailed description and implementation advice that is crucial for getting optimal results. Cutting-edge and thoroughly detailed, Horizontal Gene Transfer: Genomes in Flux examines how HGT has contributed to genome evolution and how understanding HGT impacts our ability to accurately reconstruct and comprehend the web-like evolutionary history in order to aid scientists in furthering their own research.

In this New York Times bestseller and longlist nominee for the National Book Award, “our greatest living chronicler of the natural world” (The New York Times), David Quammen explains how recent discoveries in molecular biology affect our understanding of evolution and life’s history. In the mid-1970s, scientists began using DNA sequences to reexamine the history of all life. Perhaps the most startling discovery to come out of this new field—the study of life’s diversity and relatedness at the molecular level—is horizontal gene transfer (HGT), or the movement of genes across species lines. It turns out that HGT has been widespread and important; we now know that roughly eight percent of the human genome arrived sideways by viral infection—a type of HGT. In The Tangled Tree, “the grandest tale in biology….David Quammen presents the science—and the scientists involved—with patience, candor, and flair” (Nature). We learn about the major players, such as Carl Woese, the most important little-known biologist of the twentieth century; Lynn Margulis, the notorious maverick whose wild ideas about “mosaic” creatures proved to be true; and Tsutomu Wantanabe, who discovered that the scourge of antibiotic-resistant bacteria is a direct result of horizontal gene transfer, bringing the deep study of genome histories to bear on a global crisis in public health. “David Quammen proves to be an immensely well-informed guide to a complex story” (The Wall Street Journal). In The Tangled Tree, he explains how molecular studies of evolution have brought startling recognitions about the tangled tree of life—including where we humans fit upon it. Thanks to new technologies, we now have the ability to alter even our genetic composition—through sideways insertions, as nature has long been doing. “The Tangled Tree is a source of wonder….Quammen has written a deep and daring intellectual adventure” (The Boston Globe).

This book presents the state-of-art marine metagenome research and explains the method of marine metagenomic analysis in an easy-to-understand manner. Changes in the marine environment due to global warming and pollution have become a major global problem. Maintaining a healthy marine ecosystem requires advanced environmental monitoring and assessment systems. As such, the book presents a novel metagenomic monitoring method, which has been developed for comprehensive analyses of the DNA of microorganisms living in seawater to further our understanding of the dynamics of the marine environment. The book can be used as a primer for new researchers and as a manual on experimental methods.

Phylogenies, or evolutionary trees, are the basic structures necessary to think about and analyze differences between species. Statistical, computational, and algorithmic work in this field has been ongoing for four decades now, and there have been great advances in understanding. Yet no book has summarized this work. Inferring Phylogenies does just that in a single, compact volume. Phylogenies are inferred with various kinds of data. This book concentrates on some of the central ones: discretely coded characters, molecular sequences, gene frequencies, and quantitative traits. Also covered are restriction sites, RAPDs, and microsatellites.

Bacteria are the most ubiquitous of all organisms. Responsible for a number of diseases and for many of the chemical cycles on which life depends, they are genetically adaptable. Vital to this adaptability is the existence of autonomous genetic elements-plasmids-which promote genetic exchange and recombination. The genes carried by any particular plasmid may be found in only a few individuals of any species but can also be shared with other species and thus constitute a horizontal gene pool. This book explains the various contributions that plasmids make to this pool: the replication, stable inheritance and transfer modules, the phenotypic markers they carry, the way they evolve, the ways they contribute to their host population and the approaches that we use to study and classify them. It also looks at what we know about their activity in natural communities and the way that they interact with other mobile elements to promote bacterial evolution.