Testing the processes required for coexistence mediated by spatially varying environments

2021 ◽  
Author(s):  
◽  
Isaac Towers
Keyword(s):  
Varying Environments ◽  
Spatially Varying

scholarly journals A GENERAL MODEL TO ACCOUNT FOR ENZYME VARIATION IN NATURAL POPULATIONS

Genetics ◽  
1974 ◽  
Vol 76 (4) ◽  
pp. 837-848
Author(s):  
John H Gillespie ◽  
Charles H Langley
Keyword(s):  
Genetic Polymorphism ◽  
Gene Function ◽  
General Model ◽  
Natural Populations ◽  
Environmental Variation ◽  
Biochemical Evidence ◽  
Enzyme Variation ◽  
Variable Environments ◽  
Varying Environments ◽  
Spatially Varying

ABSTRACT Approximate conditions for genetic polymorphism in temporally and spatially varying environments are presented for loci which are intermediate at the level of fitness or at the level of gene function. The conditions suggest that polymorphism will be more likely in more variable environments while unlikely in constant environments. Biochemical evidence is presented to justify the assumption of heterozygote intermediacy. Observations on natural populations are cited which substantiate the claim that allozymic polymorphism is primarily due to selection acting on environmental variation in gene function.

scholarly journals Chromosomal rearrangements represent modular cassettes for local adaptation across different geographic scales

2020 ◽  
Author(s):  
Claire Mérot ◽  
Emma Berdan ◽  
Hugo Cayuela ◽  
Haig Djambazian ◽  
Anne-Laure Ferchaud ◽  
...  
Keyword(s):  
Gene Flow ◽  
Local Adaptation ◽  
Environmental Heterogeneity ◽  
Salinity Gradient ◽  
Chromosomal Rearrangements ◽  
Fine Grained ◽  
Varying Environments ◽  
Genomic Regions ◽  
Spatially Varying ◽  
Low Coverage

AbstractAcross a species range, spatially-varying environments can drive the evolution of local adaptation. Multiples sources of environmental heterogeneity, at small and large scales, draw complex landscapes of selection which may challenge adaptation, particularly when gene flow is high. Because linkage opposes gene flow but also limits the efficiency of natural selection by contrasting pressures, the key to multidimensional adaptation may reside in the heterogeneity of recombination along the genome. Structural variants like chromosomal inversions are important recombination modifiers that form massive co-segregating genomic blocks linking together alleles at numerous genes. In this study, we investigate the influence of chromosomal rearrangements on genetic variation to ask how their contribution to adaptation with gene flow varies across geographic scales. We sampled the seaweed fly Coelopa frigida along a bioclimatic gradient of 10° of latitude, a salinity gradient and across a range of heterogeneous, patchy habitats. We assembled a high-quality genome to analyse 1,446 low-coverage whole-genome sequences, and we found large non-recombining genomic regions, including putative inversions. In contrast to the collinear regions depicting extensive gene flow, inversions and low-recombining regions differentiated populations more strongly, either along an ecogeographic cline or at a fine-grained scale. Those genomic regions were disproportionately involved in associations with environmental factors and adaptive phenotypes, albeit with contrasting patterns between the different recombination modifiers. Altogether, our results highlight the importance of recombination in shaping the selection-migration balance and show that a set of several inversions behave as modular cassettes facilitating adaptation to environmental heterogeneity at local and large scales.

scholarly journals Role of bacterial persistence in spatial population expansion

2021 ◽  
Author(s):  
Pintu Patra ◽  
Stefan Klumpp
Keyword(s):  
Population Expansion ◽  
Leading Edge ◽  
Bacterial Persistence ◽  
Persister Cells ◽  
Fitness Advantage ◽  
Expansion Speed ◽  
Phenotype Switching ◽  
Stochastic Switching ◽  
Varying Environments ◽  
Spatially Varying

Bacterial persistence, tolerance to antibiotics via stochastic phenotype switching provides a survival strategy and a fitness advantage in temporally fluctuating environments. Here we study its possible benefit in spatially varying environments using a Fisher wave approach. We study the spatial expansion of a population with stochastic switching between two phenotypes in spatially homogeneous conditions and in the presence of an antibiotic barrier. Our analytical results show that the expansion speed in growth-supporting conditions depends on the fraction of persister cells at the leading edge of the population wave. The leading edge contains a small fraction of persister cells, keeping the effect on the expansion speed minimal. The fraction of persisters increases gradually in the interior of the wave. This persister pool benefits the population when it is stalled by an antibiotic environment. In that case, the presence of persister enables the population to spread deeper into the antibiotic region and to cross an antibiotic region more rapidly. The interplay of population dynamics at the interface separating the two environments and phenotype switching in the antibiotic region results in a optimal switching rate. Overall, our results show that stochastic switching can promote population expansion in the presence of antibiotic barriers or other stressful environments.

Adaptive Social Learning Strategies in Temporally and Spatially Varying Environments

Human Nature ◽  
2012 ◽  
Vol 23 (4) ◽  
pp. 386-418 ◽  
Author(s):  
Wataru Nakahashi ◽  
Joe Yuichiro Wakano ◽  
Joseph Henrich
Keyword(s):  
Social Learning ◽  
Learning Strategies ◽  
Varying Environments ◽  
Spatially Varying ◽  
Social Learning Strategies

scholarly journals Fixation probability in spatially changing environments

1991 ◽  
Vol 58 (3) ◽  
pp. 243-251 ◽  
Author(s):  
Hidenori Tachida ◽  
Masaru Iizuka
Keyword(s):  
Local Population ◽  
Fixation Probability ◽  
Two Dimensional ◽  
Selection Coefficient ◽  
Changing Environments ◽  
Subdivided Population ◽  
Subdivided Populations ◽  
Varying Environments ◽  
And Migration ◽  
Spatially Varying

SummaryThe fixation probability of a mutant in a subdivided population with spatially varying environments is investigated using a finite island model. This probability is different from that in a panmictic population if selection is intermediate to strong and migration is weak. An approximation is used to compute the fixation probability when migration among subpopulations is very weak. By numerically solving the two-dimensional partial differential equation for the fixation probability in the two subpopulation case, the approximation was shown to give fairly accurate values. With this approximation, we show in the case of two subpopulations that the fixation probability in subdivided populations is greater than that in panmictic populations mostly. The increase is most pronounced when the mutant is selected for in one subpopulation and is selected against in the other subpopulation. Also it is shown that when there are two types of environments, further subdivision of subpopulations does not cause much change of the fixation probability in the no dominance case unless the product of the selection coefficient and the local population size is less than one. With dominance, the effect of subdivision becomes more complex.

scholarly journals Natal departure timing from spatially varying environments is dependent of individual ontogenetic status

2013 ◽  
Vol 100 (8) ◽  
pp. 761-768 ◽  
Author(s):  
Julien Cucherousset ◽  
Jean-Marc Paillisson ◽  
Jean-Marc Roussel
Keyword(s):  
Varying Environments ◽  
Spatially Varying
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