In the complex interactions of genetic and environmental factors, time represents a coordinate. Thus, it is only logical to consider biological phenomena and features in the three dimensions of space and in the dimension of time. Gedda and coworkers devoted much attention to the genetic aspects of various chronobiological events in man, and performed an extensive series of experiments to probe the many ramifications of gene-related timing phenomena.
Time factors in cytogenetics and neoplasia are discussed by considering chronobiological events as manifestations of interconnecting oscillatory phenomena in living systems. These phenomena, in turn, are regarded as the products of negative feedback control processes.
Subjects under discussion include satellite association, nondisjunction, C-mitotic duplication, endomitosis, endoreduplication, and delayed fertilization. The different theories of carcinogenesis are briefly reviewed and the time factor, as it applies to postulated mutational changes in neoplasia, is discussed.