This book is designed for use in an introductory course in genetics. In presenting their subject, the authors believe it most important that the general biological implications of genetics should never be lost from view. In accordance with this belief, they have attempted from the outset to present genetics in terms of the effects of hereditary units-in dynamic interplay with environment-on the development and function of organisms. They have also considered it important to draw examples from a wide variety of living forms, ranging from microorganisms through diverse plants and animals to man. It is their opinion that genetics, as one of the great ex. perimental sciences of our era, should be viewed as a series of problems and challenges, some of
which have been successfully met and supplanted by others. For this reason, their book follows the principle of developing genetic ideas along a logical sequence,from the simple to the complex.
The authors have further attempted to plan a certain amount of flexibility for this text in anticipation of varying situations. The first sixteen chapters provide elementary coverage of the socalled classical areas of genetics-areas that are included in almost every general course in the subject. The following three chapters are concerned with some of the details of genic effects that have emerged from recent investigations. Chapters 20 and 21 present population genetics in considerable detail,and the final three chapters emphasize the application of genetic principles. Of these, Chapters 22 and 23 should be of special interest and use to students in colleges of agriculture. The last chapter summarizes aspeects of genetics that relate to the welfare of the human individual.