Preface 



This is the transcript of an informal work- 

 shop on "The Molecular Aspects of Develop- 

 ment" held at the Nittany Lion Inn of The 

 Pennsylvania State University, University Park, 

 Pennsylvania, on July 19-21, 1965. It was or- 

 ganized by The Pennsylvania State University 

 Biophysics Department under the sponsorship 

 of the University and the National Aeronautics 

 and Space Administration. Its purpose was to 

 bring together scientists actively doing research 

 in different areas of differentiation and develop- 

 ment. Researchers from several disciplines 

 doing work on many different biological systems 

 were invited to give presentations ofthfeirwork. 

 These presentations were informal and discus- 

 sion was invited at all times. In addition to 

 those invited to give talks, participants were 

 invited from many related departments at the 

 University. A complete list of all participants 

 is given following this preface. 



This conference reflects the growing in- 

 terest in the problems of differentiation and 

 development as attacked from the molecular 

 point of view. The combined backgrounds and 

 methods of many disciplines such as biochem- 

 istry, biophysics, cell biology, genetics, micro- 

 biology, physical chemistry, physics, mathe- 

 matics and others are being brought to bear on 

 this problem and the potential reward is great. 

 An interdisciplinary approach to this problem 

 is necessary and should be emphasized. Free 

 informal communication between scientists with 

 differing backgrounds and viewpoints is essen- 

 tial. We feel that this conference was a success- 

 ful step in that direction and as such was 

 valuable to all participants. We hope that this 

 publication of the presentations and discussions 

 will be useful to the student, teacher and re- 



searcher who is interested in the problem of 

 development in biological systems. 



The conference was taped and transcribed. 

 Each participant was then given a chance to 

 rework his contribution, with the directive to 

 retain the informality and to leave spontaneous 

 discussion intermixed with presentations. The 

 slides and blackboard drawings used in most 

 presentations have been reproduced here as 

 figures, some of which were redrawn from 

 photographs of the projected slides or sketches 

 furnished by the authors. These are sometimes 

 incomplete and are merely used to illustrate 

 points in the talks. More complete data can 

 often be found in the original publications which 

 are referenced throughout. The attempt to retain 

 the spontaneous, informal flavor of the workshop 

 may result in some presentations seeming 

 incomplete and unpolished. However, since 

 spontaneity and informality are the values of a 

 conference of this type, we feel the reader should 

 be allowed as true a view of it as possible. 



We wish to thank those who made this con- 

 ference and publication possible: in particular, 

 the National Aeronautics and Space Adminis- 

 tration (Grant NsG-324), through the efforts of 

 Dr. George J. Jacobs, Chief, Physical Biology 

 Biosciences Program; The Pennsylvania State 

 University Biophysics Department and its 

 chairman. Dr. Ernest C. Pollard; and The 

 Pennsylvania State University College of Science 

 and its Dean, Dr. C. I. Noll. We are indebted 

 to Dr. Paul Ts'o for his extra effort in pre- 

 paring the summary presentation which appears 

 at the end. Finally, we wish to thank all par- 

 ticipants for their enthusiastic discussion and 

 their cooperation and hard work in preparing 

 presentations and manuscripts. 



Editors 

 May 4, 1966 



