Mobile Genetic Elements introduces the nonspecialist to the biology and genetics of mobile elements. It attempts to make the biochemistry of DNA rearrangements more accessible to embryologists and evolutionists, and to illuminate the related developmental cycles to the biochemist. The book also shows how natural the activity of mobile elements can be in diverse biological situations. The chapters describe several well-studied cases in which genetic determinants—often identified as specific nucleic acid sequences—repeatedly change their positions within or between cellular genomes. Because their genomic positions are not fixed, these determinants may conveniently be classed together under the rubric of mobile genetic elements. The book begins with a discussion of maize controlling elements. This is followed by separate chapters on the bacteriophages ? and Mu; nonviral mobile elements in bacteria; transposable Ty elements in brewer's yeast; Drosophila transposable element; and hybrid dysgenesis. Subsequent chapters cover vertebrate retroviruses; Agrobacterium oncogenesis in plants; flagellar phase variation in Salmonella; yeast mating type; and surface antigenic variation in trypanosomes.