ABSTRACT
Foot-and-mouth disease virus (FMDV), as other RNA viruses characterized to date, exists and replicates as complex and dynamic mixtures of related mutants termed viral quasispecies. In this chapter we review the conceptual origins of quasispecies, and the molecular basis and biological implications of quasispecies dynamics, as viewed through FMDV. Topics covered include genetic and antigenic heterogeneity of FMDV populations, evolution of host cell recognition, molecular epidemiology of FMDV, comparative rates of evolution of FMDV and other viruses in nature, and the mechanisms operating to maintain virus identity despite high mutation rates. Considering FMDV as a complex adaptive system, we address memory in FMDV quasispecies, the consequences of Muller’s ratchet, and virus entry into error catastrophe as a new antiviral strategy. Although the chapter reviews mainly experimental results, some connections with theoretical concepts are also addressed.
