This volume represents the Proceedings of the Twenty-Sixth Annual Biology Division Research Conference held April 9-12, 1973 in Gatlinburg, Tennessee. The subject of the symposium was Molecular Cytogenetics and the aim of the meeting was to bring together researchers interested in problems of chromosome organi- zation, activity and regulation in prokaryotes and eukaryotes. Cytological, biochemical and genetic approaches to these questions were included since the collective information gained from these disciplines provides an integrated approach to genome structure and function. The meeting...