Book excerpt: Crossover is a laboratory manual and computer program that work together to teach the principles of genetics. Designed to complement regular textbooks and classroom instruction, Crossover consists of thirty-five modules that can be tailored to fit genetics courses at several levels. Examples, interactive computer models, problems, and self-tests all help students understand difficult concepts and learn the basic mathematical skills needed to study contemporary theories of genetics, evolution, and breeding. The easy-to-use tutorial system lets students work at their own pace. Features include: - In-depth investigations of meiosis, genetic ratios, linkage mutation, natural selection, Hardy-Weinberg equilibrium, artificial selection, quantitative genetics, breeding methods, mating designs, plant patent law, and the use of molecular markers - A computer model that allows students to manipulate genetic parameters and compare outcomes. Students can observe evolution and artificial selection in action - A "Major Concepts" section at the beginning of each chapter to help students focus on the important material to be learned - A visual, easy-to-understand presentation of material - Exercises based on genetic data and analyses from actual research projects - Several stages of complexity within each area of instruction. - Instant grading of exercises - "Suggested Readings" at the end of each chapter to direct the student to related books, articles, and computer programs.