Extensively reorganized and revised with the latest data from this rapidly changing field, Lewin"s Essential GENES, Fourth Edition, provides students with a comprehensive overview of molecular biology and molecular genetics. The authors took care to carefully modify the chapter order in an effort to provide a more clear and student-friendly presentation of course material. Chapter material has been updated throughout, including a completely revised chapter on regulatory RNA, to keep pace with this advancing field. The Third Editions exceptional pedagogy enhances student learning and helps readers understand and retain key material like never before. Concept and Reasoning Checks at the end of each chapter section, End-of-Chapter Questions and Further Readings sections, as well as several categories of special topics boxes, expand and reinforce important concepts.