Expression of animal virus genomes

The world of animal viruses appears to offer an unfathomable diversity of specimens but, as the molecular biology of the replication of many viruses has been studied, a pattern of behavior has emerged. The viruses can be divided into classes, each of which has its own method of transmitting its genetic information from one generation to the next and its own style of expressing its genetic information. Although in some cases the data are still fragmentary it is possible to outline the behavior of these systems and to place them in a formal scheme. In this paper I will present such a scheme and I will discuss in some detail the behavior of three viral systems which have been investigated in my laboratory. Furthermore, I will discuss some of the implications of the existence of these viral systems in the context of the behavior of normal cells.