Chapter category: Viruses
Connections, Implications and Prospects
Quasispecies and RNA Virus Evolution: Principles and Consequences
Edited by: Esteban DomingoISBN: 1-58706-077-9
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Chapter authors:
E.Domingo, C.K. Biebricher, M. Eigen, J.J. Holland
Viruses undergo genetic change in each infected individual, pushed by mutational pressure and guided by the interplay between positive and negative selection, as discussed in preceding Chapters. The next step into the process of long-term evolution of viruses is transmission from an infected host into a susceptible one. Transmission may exert an important influence on viral evolution since it may occur between two individuals of the same host species, horizontally or vertically, or quite disparate species as with arboviruses. In the alphavirus Venezuelan equine encephalitis virus (VEEV) viral titers in the blood of horses reach 108 infectious units per ml, or a total of about 3x1012 infectious units in the blood of a single animal. These high titers probably facilitate transmission to insect vectors by uptake of blood. In humans, virus levels in blood are much lower, and therefore humans are dead-end hosts for VEEV infections (Weaver, 1998) ( Figure. 8.1). Transmission may involve massive amounts of virus (as in insects which have taken blood meals recently from viremic animals, or in human transfusions with contaminated blood) or one or few particles, such as in aerosol transmission, or from mosquitoes long after they have taken blood meals. In the latter case, transmission constitutes a natural bottleneck. A number of models have been developed to describe the spread of viral pathogens in interaction with their hosts (Anderson and May, 1991; May 1993, 1995; Garnett and Antia, 1994; Ewald, 1994; Moya and GarcÌa-Arenal, 1995; Kaslow and Evans, 1997). Recently, the evolution of viral virulence upon horizontal versus vertical transmission has been modeled with regard to the quasispecies dynamics of the infectious agent (Bergstrom et al, 1999), and the predictions of this model are in good agreement with experimental observations on fitness variations as reviewed in Chapter 7.
Additional chapters from this book:
Quantitative Molecular Evolution
E.Domingo, C.K. Biebricher, M. Eigen, J.J. Holland
Darwinian evolution, instrumental in the qualitative description of many phenomena in Biology, can and should also be formulated quantitatively. Darwin himself cited the...
Connections, Implications and Prospects
E.Domingo, C.K. Biebricher, M. Eigen, J.J. Holland
Viruses undergo genetic change in each infected individual, pushed by mutational pressure and guided by the interplay between positive and negative selection, as discussed in preceding Chapters. ...
Population Dynamics and Virus Adaptability
E.Domingo, C.K. Biebricher, M. Eigen, J.J. Holland
The meaning of fitness of living organisms has evolved since the time of Darwin (Reznick and Travis, 1996). The concept has broadened from referring to the survival of an individual to m...
Experimental Studies on Viral Quasispecies
E.Domingo, C.K. Biebricher, M. Eigen, J.J. Holland
In contrast to replication of simple, noninfectious RNA molecules in vitro analyzed in the previous Chapter, multiplication of infectious virus necessitates a concatenation of steps from entry int...
Darwinian Evolution of RNA in Vitro
E.Domingo, C.K. Biebricher, M. Eigen, J.J. Holland
In the previous Chapter we described how quantitative measurements have led to studies of Darwinian evolution in action. Simplifications and abstractions were required, and experimental sy...
Molecular Recognition and Replication Enzymes
Esteban Domingo, Christof K. Biebricher, Manfred Eigen and John J. Holland.
The special chemistry of life is centrally governed by special biomacromolecules. These are built up as linear polymers from monomeric subunits: The key biopolymers are nucleic acids (de...
Multiplication Strategies of RNA Genetic Elements
Esteban Domingo, Christof K. Biebricher, Manfred Eigen and John J. Holland.
The main steps in the life cycle of a virus are (Figure. 2.1): receptor and coreceptor recognition at the cell surface, entry into the cell, uncoating and release of the genetic materi...
Introduction
Esteban Domingo, Christof K. Biebricher, Manfred Eigen and John J. Holland.
It has always been the main aim of human intelligence to attempt to understand the bewildering diversity of the environment by recognising patterns and regularities of events. It is thus ...
