Although the phenomenon of lateral gene transfer has been known since the 1940's, it was the genomics era that has really revealed the extent and many facets of this evolutionary/genetic phenomenon. Even in the early 2000s with but a handful of genomes available it became clear that the nature of microorganisms is full of genetic exchange between lineages that are sometimes far apart. The years following this saw an explosion of genomic data, which shook the "tree of life" and also raised doubts about the most appropriate species concepts for prokaryotes. This book attempts to represent the many-fold contributions of LGT to the evolution of micro and, to an extent, macro-organisms by focusing on the areas where the Editor felt it had the largest impact: metabolic innovations and adaptations and speciation.

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).

The book focuses on the evolutionary impact of horizontal gene transfer processes on pathogenicity, environmental adaptation and biological speciation. Newly acquired genetic material has been considered as a driving force in evolution for prokaryotic genomes for many years, with recent technical developments advancing this field further. However, the extent and implications of gene transfer between prokaryotes and eukaryotes still raise controversies. This multi-authored volume introduces various means by which DNA can be exchanged, covers gene transfer between prokaryotes and their viruses as well as between bacteria and eukaryotes, such as fungi, plants and animals, and addresses the role of horizontal gene transfer in human diseases. Aspects discussed also include the relevance for virulence and drug resistance development on one hand, and for the occurrence of naturally derived antibiotics and other secondary metabolites on the other hand. This book offers new insights to anyone interested in genome evolution and the exchange of DNA between the different domains of life, the genetic toolkit for adaptation and the emergence of multidrug resistant bacteria.

This book is about mobile genes—the transfer of DNA between unrelated cells. It discusses the machinery of gene transfer and its wide-ranging biological and health consequences. Mobile DNA makes possible the development of antibiotic resistance in microbes, the conversion of harmless to pathogenic bacteria, and the triggering of cancerous growth in cells. It also contributes to human evolution. This well-illustrated volume contains an up-to-date account of a topic now seen as increasingly important, and will be invaluable for both working scientists and as a textbook for advanced courses.

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.

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.