1. Nearly 4 decades back Dr.P.N. Rao and Johnson did some elegant experiments using the cell fusion technique to understand the functional relationship between the phases of cell cycle.
2. These experiments have, for the first time provided evidence that the progression of cells through the cell cycle is sequential and unidirectional and are controlled by a series of chemical signals that can diffuse freely between nucleus and cytoplasm.
3. These experiments revealed for the first time the structure of interphase chromosomes that are not ordinarily visible under the microscope.
4. These experiments are considered to be a ‘milestone’ in the cell cycle studies.
