scope:

Preface

The understanding of how genes influence the development and maintenance of obesity and its complications, such as type 2 diabetes and cardiovascular disease, has increased dramatically in recent decades, not in the least due to the development of tools for investigating genes and gene functions (i.e., large-scale genome screening). However, there is still much to learn. During this period several books on this topic have been published, but advances have been so rapid that a new one offering an updated overview of where we are now, the current front line questions, the technology that may help answer the questions, as well as future challenges and opportunities, is justified.

For some years, an annually updated comprehensive catalogue of findings on the genetics of obesity, defined as the role of interindividual genetic variation, has been published under the name, "The Obesity Gene Map," and the information it contains has been compiled in a useful website (www.obesitygene.pbrc. edu). However, for researchers and teachers approaching this field, there is a need to combine this source with an overview of the genomics of obesity, by which we mean the study of gene functions, the regulation of gene functions, and downstream relationships, including the interaction with environmental exposures in the broadest sense. Insight into possibilities and limitations is also needed to achieve a reasonable understanding of the current status and progress in the field. We have attempted to cover all the relevant main topics in the study of the genomics of human obesity, which clearly must also include rodent and nonvertebrate research. We have included both phenotypic quantitative genetics and molecular genetics, and we have added epigenetics and postgenomic processes, in addition to genotype-phenotype relationships.

On the other hand, the book does not intend to provide a completely up-to-date and comprehensive picture of the field. In view of the time it takes to produce a book and the amount of information emerging almost daily from many different laboratories, this would not be feasible. Since we began working on the book, several new discoveries have been made, and new technologies have come to prevailing use. A good example is the recent discovery, in a genome-wide search for genes associated with type 2 diabetes, of a very strong statistical association between a common, single nucleotide polymorphism in the FTO gene and the level of body mass index in the general population, published just before the final typesetting (www.scienceexpress.org 12 April, 2007). Aiming to incorporate each new important finding and technological development would make the writing of the book a never-ending story.

Our intention is rather to present a series of chapters in which competent and experienced experts, still actively involved in research in the field, give their current view on the topic of the chapter they were assigned to write. We have given contributors the freedom to set their own priorities in what and how they want to present their material within each chapter, with no editorial interference. This has a number of important implications for the reader. First, each chapter may be read as if it is an independent review article; second, there may well be repetition and even discordance among chapters, reflecting the diversity of opinions on the same issues; third, the selection of references in each chapter is based on what the contributors feel represents the core literature on the particular topic; fourth, the editors may not always share the opinions of the authors on various issues. The terminology and abbreviations used also reflect current customs in a particular area, except that we have used gene and gene product names and abbreviations in accordance with international standards.