It is suggested that structured habitats are more favorable for the evolution of colicinogenic bacteria than liquid cultures, which exist as randomly distributed individuals and as single-clone colonies.
We present a model of resource-limited population growth, competition, and predation based on what we believe to be biologically realistic assumptions about the relationship between resources and the…
Results show that deleterious mutations are generated at a sufficiently high rate to advance Muller's ratchet in an RNA virus and that beneficial, backward and compensatory mutations cannot stop theRatchet in the observed range of fitness decrease.
The theoretical and empirical considerations imply that strong genetic constraint on the selective accessibility of trajectories to high fitness genotypes may exist and suggest specific areas of investigation for future research.
This work focuses on the first kind of robustness—genetic robustness)—and survey three growing avenues of research: measuring genetic robustness in nature and in the laboratory; understanding the evolution of genetic robusts; and exploring the implications of genetic resilientness for future evolution.
It is shown that the fitness of the high-multiplicity phage relative to their ancestors generates a pay-off matrix conforming to the prisoner's dilemma strategy of game theory, in which defection (selfishness) evolves, despite the greater fitness pay-offs that would result if all players were to cooperate.
A new experimental test of Fisher's geometric model of adaptive evolution subjected the bacteriophage phi6 to intensified genetic drift in small populations and caused viral fitness to decline through the accumulation of a deleterious mutation, which confirmed Fisher's main prediction that advantageous mutations of small effect should be more common.
The genetic mosaicism hypothesis (GMH) proposed that arborescent plants accumulate spontaneous mutations and become genetically mosaic as they grow, which can contribute more to standing genetic variation in populations than do gametic mutations and thereby can increase plant evolutionary rates.
The fit of these observations to some previously developed theory of resource—limited growth, competition and predation is discussed and a mechanism to account for the persistence of these communities is presented.
Evidence that positive epistasis is characteristic of deleterious mutations in the RNA bacteriophage φ6 is provided and the results suggest that even random mutations impact the degree of canalization, the buffering of a phenotype against genetic and environmental perturbations.