Genetic analysis of echovirus 11 variability in adsorption to human erythrocytes

Abstract

The frequency of nonhemagglutinating (h-) mutants was determined in hemagglutinating (HA) clones of echovirus 11. The HA clones were derived from the prototype strain Gregory and a clinical isolate of echovirus 11. The h- mutants were found at a constant frequency of 3.0 x 10(-5) (mean value) in the HA clones derived from both strains. Since the conditions of the population equilibrium of HA clones and neutrality of the mutation were satisfied, it was proposed that the observed frequency of h- mutants occurred as a result of a point mutation. The frequency of h+ revertants at the second passage of h- mutant clone was 9.1 x 10(-5). Hence the frequency of reversion suggests that the number of potential sites of back mutation was restricted.

Mathematical modelling of mutant accumulation kinetics in a cloned viral population

“…The value p 1 = 2 × 10 −5 is the experimentally found rate of poliovirus mutation due to a specific transition [2]. The value p 2 = 9.1 × 10 −5 is an estimate for the recovery rate of a trait and obtained in the experiment described in [15]. The value p 2 = 9.1 × 10 −5 is an estimate for the recovery rate of a trait and obtained in the experiment described in [15].…”

“…This would allow one to mathematically justify the assumption [15] regarding the molecular type of mutation. The term 'normal' is used in this paper to denote a virus that has hemagglutinating properties and corresponds to the term 'wild type'.…”

“…The results of genetic analysis of echovirus 11 variability in adsorption to human erythrocytes, which is revealed by a laboratory test as a hemagglutination phenomenon, were partly published earlier [15]. The genetic analysis was made on cloned viral populations that represented the progeny of single viruses.…”

“…Mutant frequency in the biological Mutant frequency in the numerical experiment (by the data in [15]) experiment (p 1 = 2.5 × 10 −6 ) 01 (4.7 ± 4.7) × 10 −5 (4.4 ± 0.1) × 10 −5 08…”

“…tage of the hemagglutinating variants over nonhemagglutinating ones [15] was not taken into account. Since this advantage became evident only in experiments with a prolonged replication of nonhemagglutinating mutant clones, this effect could be disregarded in the given model, i.e.…”