Preface 



Althuugli gc'iK'tics is one of the youngest subdivisions of l^iology, it has 

 come to occupy a central jiosition and to serve as a focal point not only 

 for the interests of biologists, but also for diverse groui)s who use desig- 

 nations such as biochemists, physical chemists, biophysicists, virologists, 

 geneticists, and cytologists or cell biologists. A consideration of the 

 groups involved indicates that the emphasis in this work has shifted 

 from the classical approaches of genetics to a molecular view of the 

 mechanism of heredity; therefore "Molecular Genetics" is an appropriate 

 title. Many of the problems are being considered from the molecular 

 point of view even though the structures and mechanisms involved cannot 

 yet be precisely defined in molecular terms. 



In a rapidly developing field of science, the ability to keej) informed 

 of progress becomes a major problem. When the groups involved have 

 such diverse backgrounds, interests, and locations among the various 

 established disciplines, the task becomes even more difficult. Fortunately 

 there is no dearth of scientific meetings and special symposia which 

 consider various aspects of the ill-defined area to be included under 

 molecular genetics. Many of these meetings and discussions result in 

 publications. However, a need was felt for a more consistent and thor- 

 ough coverage, which would highlight some of the interesting and, hope- 

 fully, significant advances, provide a useful reference source, and allow 

 our interested colleagues, who work in these or related areas, to bring 

 themselves up to date. The material should also be useful for teaching 

 and training at the graduate and upper undergraduate levels. Only time 

 can render a verdict on the success of these aims. 



As indicated by the designation of this as Part I, several imi)or- 

 tant topics in molecular genetics have been missed or touched lightly. 

 Although plans are still indefinite we hope to fill the gaps in a second 

 and possibly third volume. Some of the most exciting concepts are still 

 not sufficiently ciystallized to warrant recording even in an advanced 

 work such as this. As some degree of stabilization occurs, and willing 

 and able writers are found, we trust the gaps will be closed. Nevertheless, 

 a unity and narrative form were kept in mind in planning the volume. 

 The first five chapters are concerned with DNA — its replication and 

 organization into chromosomes, control mechanisms in its replication, 

 and its mutability. The next two chapters deal with the biosynthesis of 

 RNA, its role in translating and transferring the genetic information. 



