Polyploid And Hybrid Genomics

Polyploidy plays an important role in biological diversity, trait improvement, and plant species survival. Understanding the evolutionary phenomenon of polyploidy is a key challenge for plant and crop scientists. This book is made up of contributions from leading researchers in the field from around the world, providing a truly global review of the subject. Providing broad-ranging coverage, and up-to-date information from some of the world’s leading researchers, this book is an invaluable resource for geneticists, plant and crop scientists, and evolutionary biologists.

Polyploidy – whole-genome duplication (WGD) – is a fundamental driver of biodiversity with significant consequences for genome structure, organization, and evolution. Once considered a speciation process common only in plants, polyploidy is now recognized to have played a major role in the structure, gene content, and evolution of most eukaryotic genomes. In fact, the diversity of eukaryotes seems closely tied to multiple WGDs. Polyploidy generates new genomic interactions – initially resulting in “genomic and transcriptomic shock” – that must be resolved in a new polyploid lineage. This process essentially acts as a “reset” button, resulting in genomic changes that may ultimately promote adaptive speciation. This book brings together for the first time the conceptual and theoretical underpinnings of polyploid genome evolution with syntheses of the patterns and processes of genome evolution in diverse polyploid groups. Because polyploidy is most common and best studied in plants, the book emphasizes plant models, but recent studies of vertebrates and fungi are providing fresh perspectives on factors that allow polyploid speciation and shape polyploid genomes. The emerging paradigm is that polyploidy – through alterations in genome structure and gene regulation – generates genetic and phenotypic novelty that manifests itself at the chromosomal, physiological, and organismal levels, with long-term ecological and evolutionary consequences.

This volume provides protocols on evidence for polyploidy and how it can be unveiled. Chapters guide readers through evolutionary experiments, measure effects of polyploidy, evidence for (remnants of) ancient WGDs, models of chromosome number evolution, population genomics approaches to study polyploidy, analysing genetic data from polyploid populations, Phylogenetic and phylogenomic methods, gene expression, gene regulation, unicellular alga (Chlamydomonas), and a fast-growing duckweed (Spirodela). Written in the format of the highly successful Methods in Molecular Biology series, each chapter includes an introduction to the topic, lists necessary materials and reagents, includes tips on troubleshooting and known pitfalls, and step-by-step, readily reproducible protocols. Authoritative and cutting-edge, Polyploidy: Method and Protocols aims to be of interest to experimental and computational (evolutionary) biologists, molecular biologists, and biotechnologists.

Many of our current agricultural crops are natural or agricultural hybrids (between two or more species), or polyploids (containing more than one genome or set of chromosomes). These include potato, oats, cotton, oilseed rape, wheat, strawberries, kiwifruit, banana, seedless watermelon, triticale and many others. Polyploidy and hybridization can also be used for crop improvement: for example, to introgress disease resistance from wild species into crops, to produce seedless fruits for human consumption, or even to create entirely new crop types. Some crop genera have hundreds of years of interspecific hybridization and ploidy manipulation behind them, while in other genera use of these evolutionary processes for crop improvement is still at the theoretical stage. This book brings together stories and examples by expert researchers and breeders working in diverse crop genera, and details how polyploidy and hybridization processes have shaped our current crops, how these processes have been utilized for crop improvement in the past, and how polyploidy and interspecific hybridization can be used for crop improvement in the future.

This second of two volumes on Plant Genome Diversity provides, in 20 chapters, insights into the structural evolution of plant genomes with all its variations. Starting with an outline of plant phylogeny and its reconstruction, the second part of the volume describes the architecture and dynamics of the plant cell nucleus, the third examines the evolution and diversity of the karyotype in various lineages, including angiosperms, gymnosperms and monilophytes. The fourth part presents the mechanisms of polyploidization and its biological consequences and significance for land plant evolution. The fifth part deals with genome size evolution and its biological significance. Together with Volume I, this comprehensive book on the plant genome is intended for students and professionals in all fields of plant science, offering as it does a convenient entry into a burgeoning literature in a fast-moving field.