Fig 1.
Fundamental equations of quasispecies and representation of mutant spectra.
The equations are the mathematical expression of the major concepts implied by quasispecies theory. The first equation describes the change of concentration of molecule i as a function of replication parameters, and its production from other molecules of the same ensemble. The second equation is the error threshold relationship, indicating the maximum amount of information (ʋmax) and the maximum average error rate pmax (p = 1- q; q is the copying fidelity) for maintenance of genetic information. Terms are defined in the box on the right. Below, an evolving mutant spectrum (with mutations represented as symbols on the genomes), with an invariant consensus sequence. Details in [2].
Fig 2.
Flow of conceptual derivations of quasispecies theory for viral populations, and some biological consequences.
Fig 3.
Scope of viral population dynamics.
Upon isolation from an infected host (middle boxes), a virus sample may be adapted to cultured cells and subjected to large population or bottleneck transfers (left box), or be adapted to a different host in vivo (right box). Relevant adaptive mutations are highlighted with colored symbols.
Fig 4.
Illustration of bottleneck of different severity, defined by the different arrows acting on the entire population.
Symbols represent mutation types.
Table 1.
Summary of main concepts related to quasispecies and their implications a.