Trata da modelagem teórica de um experimento que simula in vitro a evolução da aptidão (fitness) de uma população de virus.

We consider a nonlinear partial differential equation of conservation type to describe the dy- namics of vesicular stomatitis virus observed in aliquots of fixed particle number taken from an evolving clone at periodic intervals of time [5]. The changes in time behavior of fitness function noticed in experimental data are related to a crossover exhibited by the solutions to this equation in the transient regime for pulse-like initial conditions. As a consequence, the average replication rate of the population is predicted to reach a plateau as a power t1/ 2