This "methods" manual for molecular genetics laboratories concentrates on the application of the most up-to-date methods. It stresses how the methods relate to particular goals and how recommended book theory is best translated into practice. It incorporates the latest techniques in genetic investigation and gives an examination of the gastrointestinal tract and the diseases that affect it. The work is intended to promote an approach which encourages awareness of the earliest manifestations of a disease and also focuses some attention on the pathophysiological basis of gastro intestinal disease. It attempts to introduce the methods of recombinant DNA technology to haematologists, the chapters are intended to comprise a "core curriculum", providing the essential techniques needed to introduce recombinant DNA technology into a typical research laboratory. Each author has attempted to provide the rationale for a particular group of methods, an overview of the utility of the method, a step-by-step protocol of the actual method and any pitfalls about which one must be cognizant in order to develop the method successfully. In addition, each author has included brief discussions of selected alternate techniques.