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.

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.

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.

An exploration of the raw power of genetic material to refashion itself to any purpose... Virtually all organisms contain multiple mobile DNAs that can move from place to place, and in some organisms, mobile DNA elements make up a significant portion of the genome. Mobile DNA III provides a comprehensive review of recent research, including findings suggesting the important role that mobile elements play in genome evolution and stability. Editor-in-Chief Nancy L. Craig assembled a team of multidisciplinary experts to develop this cutting-edge resource that covers the specific molecular mechanisms involved in recombination, including a detailed structural analysis of the enzymes responsible presents a detailed account of the many different recombination systems that can rearrange genomes examines the tremendous impact of mobile DNA in virtually all organisms Mobile DNA III is valuable as an in-depth supplemental reading for upper level life sciences students and as a reference for investigators exploring new biological systems. Biomedical researchers will find documentation of recent advances in understanding immune-antigen conflict between host and pathogen. It introduces biotechnicians to amazing tools for in vivo control of designer DNAs. It allows specialists to pick and choose advanced reviews of specific elements and to be drawn in by unexpected parallels and contrasts among the elements in diverse organisms. Mobile DNA III provides the most lucid reviews of these complex topics available anywhere.

Research on gene drive systems is rapidly advancing. Many proposed applications of gene drive research aim to solve environmental and public health challenges, including the reduction of poverty and the burden of vector-borne diseases, such as malaria and dengue, which disproportionately impact low and middle income countries. However, due to their intrinsic qualities of rapid spread and irreversibility, gene drive systems raise many questions with respect to their safety relative to public and environmental health. Because gene drive systems are designed to alter the environments we share in ways that will be hard to anticipate and impossible to completely roll back, questions about the ethics surrounding use of this research are complex and will require very careful exploration. Gene Drives on the Horizon outlines the state of knowledge relative to the science, ethics, public engagement, and risk assessment as they pertain to research directions of gene drive systems and governance of the research process. This report offers principles for responsible practices of gene drive research and related applications for use by investigators, their institutions, the research funders, and regulators.

Nearly four decades ago Richard Dawkins published The Selfish Gene, famously reducing humans to “survival machines” whose sole purpose was to preserve “the selfish molecules known as genes.” How these selfish genes work together to construct the organism, however, remained a mystery. Standing atop a wealth of new research, The Society of Genes now provides a vision of how genes cooperate and compete in the struggle for life. Pioneers in the nascent field of systems biology, Itai Yanai and Martin Lercher present a compelling new framework to understand how the human genome evolved and why understanding the interactions among our genes shifts the basic paradigm of modern biology. Contrary to what Dawkins’s popular metaphor seems to imply, the genome is not made of individual genes that focus solely on their own survival. Instead, our genomes comprise a society of genes which, like human societies, is composed of members that form alliances and rivalries. In language accessible to lay readers, The Society of Genes uncovers genetic strategies of cooperation and competition at biological scales ranging from individual cells to entire species. It captures the way the genome works in cancer cells and Neanderthals, in sexual reproduction and the origin of life, always underscoring one critical point: that only by putting the interactions among genes at center stage can we appreciate the logic of life.

Genetic engineering and biotechnology along with conventional breeding have played an important role in developing superior cultivars by transferring economically important traits from distant, wild and even unrelated species to the cultivated varieties which otherwise could not have been possible with conventional breeding. There is a vast amount of literature pertaining to the genetic improvement of crops over last few decades. However, the wonderful results achieved by crop scientists in food legumes’ research and development over the years are scattered in different journals of the World. The two volumes in the series ‘Alien Gene Transfer in Crop Plants’ address this issue and offer a comprehensive reference on the developments made in major food crops of the world. These volumes aim at bringing the contributions from globally renowned scientists at one platform in a reader-friendly manner. The 1st volume entitled, ‘Alien Gene Transfer in Crop Plants: Innovations, Methods and Risk Assessment” will deal exclusively with the process and methodology. The contents of this volume have been designed to appraise the readers with all the theoretical and practical aspects of wide hybridization and gene transfer like processes and methods of gene transfer, role of biotechnology with special reference to embryo rescue, genetic transformation, protoplast fusion and molecular marker technology, problems such as cross incompatibility and barriers to distant hybridization and solutions to overcome them. Since wild and weedy relatives of crop plants may have negative traits associated with them, there are always possibilities of linkage drag while transferring alien alleles. Therefore, problems and limitations of alien gene transfer from these species will also be discussed in this series. Further, the associated risks with this and assessment of risks will also be given due weightage.