Bacterial Genomes

This book presents the application of genomic tools to examine bacterial adaptation. The emphasis is on data analysis and interpretation.

A wide range of microbiologists, molecular biologists, and molecular evolutionary biologists will find this new volume of singular interest. It summarizes the present knowledge about the structure and stability of microbial genomes, and reviews the techniques used to analyze and fingerprint them. Maps of approximately thirty important microbes, along with articles on the construction and relevant features of the maps are included. The volume is not intended as a complete compendium of all information on microbial genomes, but rather focuses on approaches, methods and good examples of the analysis of small genomes.

The first bacterial genome, Haemophilus influenzae, was completely sequenced, annotated, and published in 1995. Today, more than 200 prokaryotic (archaeal and bacterial) genomes have been completed and over 500 prokaryotic genomes are in va- ous stages of completion. Seventeen eukaryotic genomes plus four eukaryotic chro- somes have been completed. The concept of achieving better understanding of an organism through knowledge of the complete genomic sequence was first demonstrated in 1978 when the first bacteriophage genome, X174, was sequenced. Complete genomic sequences of prokaryotes have led to a better understanding of the biology and evolution of the microbes, and, for pathogens, facilitated identification of new vaccine candidates, putative virulence genes, targets for antibiotics, new strategy for rapid diagnosis, and investigation of bacteria–host interactions and disease mec- nisms. Recent increased interest in microbial pathogens and infectious diseases is largely attributed to the re-emergence of infectious diseases like tuberculosis, emergence of new infectious diseases like AIDS and severe acute respiratory syndrome, the problem of an increasing rate of emergence of antibiotic-resistant variants of pathogens, and the fear of bioterrorism. Microbes are highly diverse and abundant in the biosphere. Less than 1% of these morphologically identified microbes can be cultured in vitro using standard techniques and conditions. With such abundance of microbes in nature, we can expect to see new variants and new species evolve and a small number will emerge as pathogens to humans.

The genetic information contained in DNA is not static, especially in bacterial DNA. It is capable of recombining with other DNA sequences and transferring to other bacteria. These processes allow bacteria to rapidly respond to their environment and are also important in production of disease and the spread of antibiotic resistance. This book is concerned with the mechanisms underlying these dynamic processes in bacterial DNA.

Our understanding of bacterial genetics has progressed as the genomics field has advanced. Genetics and genomics complement and influence each other; they are inseparable. Under the novel insights from genetics and genomics, once-believed borders in biology start to fade: biological knowledge of the bacterial world is being viewed under a new light and concepts are being redefined. Species are difficult to delimit and relationships within and between groups of bacteria – the whole concept of a tree of life – is hotly debated when dealing with bacteria. The DNA within bacterial cells contains a variety of features and signals that influence the diversity of the microbial world. This text assumes readers have some knowledge of genetics and microbiology but acknowledges that it can be varied. Therefore, the book includes all of the information that readers need to know in order to understand the more advanced material in the book.

Over 500 prokaryotic genomes have been sequenced to date, and thousands more have been planned for the next few years. While these genomic sequence data provide unprecedented opportunities for biologists to study the world of prokaryotes, they also raise extremely challenging issues such as how to decode the rich information encoded in these genomes. This comprehensive volume includes a collection of cohesively written chapters on prokaryotic genomes, their organization and evolution, the information they encode, and the computational approaches needed to derive such information. A comparative view of bacterial and archaeal genomes, and how information is encoded differently in them, is also presented. Combining theoretical discussions and computational techniques, the book serves as a valuable introductory textbook for graduate-level microbial genomics and informatics courses.

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.

Overview and Goals This book describes how to visualize and compare bacterial genomes. Sequencing technologies are becoming so inexpensive that soon going for a cup of coffee will be more expensive than sequencing a bacterial genome. Thus, there is a very real and pressing need for high-throughput computational methods to compare hundreds and thousands of bacterial genomes. It is a long road from molecular biology to systems biology, and in a sense this text can be thought of as a path bridging these ? elds. The goal of this book is to p- vide a coherent set of tools and a methodological framework for starting with raw DNA sequences and producing fully annotated genome sequences, and then using these to build up and test models about groups of interacting organisms within an environment or ecological niche. Organization and Features The text is divided into four main parts: Introduction, Comparative Genomics, Transcriptomics and Proteomics, and ? nally Microbial Communities. The ? rst ? ve chapters are introductions of various sorts. Each of these chapters represents an introduction to a speci? c scienti? c ? eld, to bring all readers up to the same basic level before proceeding on to the methods of comparing genomes. First, a brief overview of molecular biology and of the concept of sequences as biological inf- mation are given.