which contains simple problems that illustrate basic genetic analysis,and the Testing Your Knowledge section,which contains more complex problems that inte- grate different concepts and techniques.A set of Questions and Problems follows the worked-out problems so that students can enhance their understanding of the con- cepts in the chapter and develop their analytical skills.Another section,Genomics on the Web,poses issues that can be investigated by going to the National Center for Biotechnology Information web site.In this section,students can learn how to use the vast repository of genetic information that is accessible via that web site, and they can apply that information to specific problems.Each chapter also has a Problen-Solving Skills feature,which poses a problem,lists the pertinent facts and concepts,and then analyzes the problem and presents a solution.Finally,we have added a new feature,Solve It,to provide students with opportunities to test their understanding of concepts as they encounter them in the text.Each chapter poses two Solve It problems;step-by-step explanations of the answers are presented on the book's web site,some in video format. Content and Organization of the sixth Edition The organization of this edition of Principles of Genetics is similar to that of the previous edition.However,the content has been sifted and winnowed to allow thoughtful updat- ing.In selecting material to be included in this edition of Principles of Genetics,we have tried to be comprehensive but not encyclopedic. The text comprises 24 chapters-one less than the previous edition.Chapters 1-2 introduce the science of genetics,basic features of cellular reproduction,and some of the model genetic organisms;Chapters 3-8 present the concepts of classical genetics and the basic procedures for the genetic analysis of microorganisms;Chapters 9-13 present the topics of molecular genetics,including DNA replication,transcription,translation,and mutation;Chapters 14-17 cover more advanced topics in molecular genetics and genom- ics;Chapters 18-21 deal with the regulation of gene expression and the genetic basis of development,immunity,and cancer;Chapters 22-24 present the concepts of quantita- tive,population,and evolutionary genetics. As in previous editions,we have tried to create a text that can be adapted to different course formats.Many instructors prefer to present the topics in much the same way as we have,starting with classical genetics,progressing into molecular genetics,and finishing with quantitative,population,and evolutionary genetics.However this text is constructed so that teachers can present topics in different orders.They may,for example,begin with basic molecular genetics(Chapters 9-13),then present classical genetics(Chapters 3-8), progress to more advanced topics in molecular genetics(Chapters 14-21),and finish the course with quantitative,population,and evolutionary genetics(Chapters 22-24). Alternatively,they may wish to insert quantitative and population genetics between classical and molecular genetics. Pedagogy of the Sixth Edition The text includes special features designed to emphasize the relevance of the topics dis- cussed,to facilitate the comprehension of important concepts,and to assist students in evaluating their grasp of these concepts. .Chapter-Opening Vignette.Each chapter opens with a brief story that highlights the significance of the topics discussed in the chapter. ● Chapter Outline.The main sections of each chapter are conveniently listed on the chapter's first page. ● Section Summary.The content of each major section of text is briefly summarized at the beginning of that section.These opening summaries focus attention on the main ideas developed in a chapter.v which contains simple problems that illustrate basic genetic analysis, and the Testing Your Knowledge section, which contains more complex problems that inte￾grate different concepts and techniques. A set of Questions and Problems follows the worked-out problems so that students can enhance their understanding of the con￾cepts in the chapter and develop their analytical skills. Another section, Genomics on the Web, poses issues that can be investigated by going to the National Center for Biotechnology Information web site. In this section, students can learn how to use the vast repository of genetic information that is accessible via that web site, and they can apply that information to specific problems. Each chapter also has a Problem-Solving Skills feature, which poses a problem, lists the pertinent facts and concepts, and then analyzes the problem and presents a solution. Finally, we have added a new feature, Solve It, to provide students with opportunities to test their understanding of concepts as they encounter them in the text. Each chapter poses two Solve It problems; step-by-step explanations of the answers are presented on the book’s web site, some in video format. Content and Organization of the Sixth Edition The organization of this edition of Principles of Genetics is similar to that of the previous edition. However, the content has been sifted and winnowed to allow thoughtful updat￾ing. In selecting material to be included in this edition of Principles of Genetics, we have tried to be comprehensive but not encyclopedic. The text comprises 24 chapters—one less than the previous edition. Chapters 1–2 introduce the science of genetics, basic features of cellular reproduction, and some of the model genetic organisms; Chapters 3–8 present the concepts of classical genetics and the basic procedures for the genetic analysis of microorganisms; Chapters 9–13 present the topics of molecular genetics, including DNA replication, transcription, translation, and mutation; Chapters 14–17 cover more advanced topics in molecular genetics and genom￾ics; Chapters 18–21 deal with the regulation of gene expression and the genetic basis of development, immunity, and cancer; Chapters 22–24 present the concepts of quantita￾tive, population, and evolutionary genetics. As in previous editions, we have tried to create a text that can be adapted to different course formats. Many instructors prefer to present the topics in much the same way as we have, starting with classical genetics, progressing into molecular genetics, and finishing with quantitative, population, and evolutionary genetics. However this text is constructed so that teachers can present topics in different orders. They may, for example, begin with basic molecular genetics (Chapters 9–13), then present classical genetics (Chapters 3–8), progress to more advanced topics in molecular genetics (Chapters 14–21), and finish the course with quantitative, population, and evolutionary genetics (Chapters 22–24). Alternatively, they may wish to insert quantitative and population genetics between classical and molecular genetics. Pedagogy of the Sixth Edition The text includes special features designed to emphasize the relevance of the topics dis￾cussed, to facilitate the comprehension of important concepts, and to assist students in evaluating their grasp of these concepts. • Chapter-Opening Vignette. Each chapter opens with a brief story that highlights the significance of the topics discussed in the chapter. • Chapter Outline. The main sections of each chapter are conveniently listed on the chapter’s first page. • Section Summary. The content of each major section of text is briefly summarized at the beginning of that section. These opening summaries focus attention on the main ideas developed in a chapter