Evolutionary Rescue in Structured Populations

2014 ◽  
Vol 183 (1) ◽  
pp. E17-E35 ◽  
Author(s):  
Hildegard Uecker ◽  
Sarah P. Otto ◽  
Joachim Hermisson
Keyword(s):  
Structured Populations ◽  
Evolutionary Rescue

scholarly journals Between migration load and evolutionary rescue: dispersal, adaptation and the response of spatially structured populations to environmental change

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132795 ◽  
Author(s):  
Elizabeth C. Bourne ◽  
Greta Bocedi ◽  
Justin M. J. Travis ◽  
Robin J. Pakeman ◽  
Rob W. Brooker ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Structured Populations ◽  
Evolutionary Potential ◽  
Beneficial Effects ◽  
Individual Fitness ◽  
Spatially Structured Populations ◽  
Local Selection ◽  
Evolutionary Response ◽  
Evolutionary Rescue ◽  
Opposing Effects

The evolutionary potential of populations is mainly determined by population size and available genetic variance. However, the adaptability of spatially structured populations may also be affected by dispersal: positively by spreading beneficial mutations across sub-populations, but negatively by moving locally adapted alleles between demes. We develop an individual-based, two-patch, allelic model to investigate the balance between these opposing effects on a population's evolutionary response to rapid climate change. Individual fitness is controlled by two polygenic traits coding for local adaptation either to the environment or to climate. Under conditions of selection that favour the evolution of a generalist phenotype (i.e. weak divergent selection between patches) dispersal has an overall positive effect on the persistence of the population. However, when selection favours locally adapted specialists, the beneficial effects of dispersal outweigh the associated increase in maladaptation for a narrow range of parameter space only (intermediate selection strength and low linkage among loci), where the spread of beneficial climate alleles is not strongly hampered by selection against non-specialists. Given that local selection across heterogeneous and fragmented landscapes is common, the complex effect of dispersal that we describe will play an important role in determining the evolutionary dynamics of many species under rapidly changing climate.

scholarly journals Fragmentation helps evolutionary rescue in highly connected habitats

2020 ◽  
Author(s):  
Matteo Tomasini ◽  
Stephan Peischl
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Environmental Conditions ◽  
Structured Populations ◽  
Adaptive Introgression ◽  
Spatially Structured Populations ◽  
Species Survival ◽  
Evolutionary Rescue ◽  
The Face ◽  
Population Sizes

AbstractGenetic variation and population sizes are critical factors for successful adaptation to novel environmental conditions. Gene flow between sub-populations is a potent mechanism to provide such variation and can hence facilitate adaption, for instance by increasing genetic variation or via adaptive introgression. On the other hand, if gene flow between different habitats is too strong, locally beneficial alleles may not be able to establish permanently. In the context of evolutionary rescue, intermediate levels of gene flow are therefore often optimal for maximizing a species chance for survival in meta-populations without spatial structure. To which extent and under which conditions gene flow facilitates or hinders evolutionary rescue in spatially structured populations remains unresolved. We address this question and show that detrimental effects of gene flow can become negligible in spatially structured populations subject to a gradual deterioration of environmental conditions. If the number of sub-populations is sufficiently large, we find a positive relationship between the amount of gene flow and the survival chance of the population. A counter-intuitive conclusion is that increased fragmentation can facilitate species survival in the face of severe environmental change if migration is common but limited to neighboring sub-populations.

scholarly journals When does gene flow facilitate evolutionary rescue?

2019 ◽  
Author(s):  
Matteo Tomasini ◽  
Stephan Peischl
Keyword(s):  
Gene Flow ◽  
Structured Populations ◽  
Migration Rates ◽  
Evolutionary Rescue ◽  
Theoretical Question ◽  
The Impact ◽  
Experimental And Theoretical Studies ◽  
Positive Effect ◽  
Theoretical Results ◽  
Traditional Population

AbstractExperimental and theoretical studies have highlighted the impact of gene flow on the probability of evolutionary rescue in structured habitats. Mathematical modelling and simulations of evolutionary rescue in spatially or otherwise structured populations showed that intermediate migration rates can often maximize the probability of rescue in gradually or abruptly deteriorating habitats. These theoretical results corroborate the positive effect of gene flow on evolutionary rescue that has been identified in experimental yeast populations. The observations that gene flow can facilitate adaptation are in seeming conflict with traditional population genetics results that show that gene flow usually hampers (local) adaptation. Identifying conditions for when gene flow facilitates survival chances of populations rather than reducing them remains a key unresolved theoretical question. We here present a simple analytically tractable model for evolutionary rescue in a two-deme model with gene flow. Our main result is a simple condition for when migration facilitates evolutionary rescue, as opposed as no migration. We further investigate the roles of asymmetries in gene flow and / or carrying capacities, and the effects of density regulation and local growth rates on evolutionary rescue.

scholarly journals Frequency responses of age-structured populations: Pacific salmon as an example

2010 ◽  
Vol 78 (4) ◽  
pp. 239-249 ◽  
Author(s):  
Lee Worden ◽  
Louis W. Botsford ◽  
Alan Hastings ◽  
Matthew D. Holland
Keyword(s):  
Pacific Salmon ◽  
Structured Populations ◽  
Frequency Responses ◽  
Age Structured

scholarly journals The Population Genetics of Evolutionary Rescue in Diploids: X Chromosomal versus Autosomal Rescue

2020 ◽  
Vol 195 (3) ◽  
pp. 561-568
Author(s):  
Robert L. Unckless ◽  
H. Allen Orr
Keyword(s):  
Population Genetics ◽  
Evolutionary Rescue

scholarly journals Hierarchical Analysis of Nucleotide Diversity in Geographically Structured Populations

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 629-639 ◽  
Author(s):  
Kent E Holsinger ◽  
Roberta J Mason-Gamer
Keyword(s):  
Nucleotide Diversity ◽  
Restriction Site ◽  
Rooted Tree ◽  
Structured Populations ◽  
Hierarchical Analysis ◽  
Restriction Site Variation ◽  
Hierarchical Levels ◽  
Site Variation ◽  
The Mean ◽  
Mean Time

Abstract Existing methods for analyzing nucleotide diversity require investigators to identify relevant hierarchical levels before beginning the analysis. We describe a method that partitions diversity into hierarchical components while allowing any structure present in the data to emerge naturally. We present an unbiased version of Nei's nucleotide diversity statistics and show that our modification has the same properties as Wright's  F  ST. We compare its statistical properties with several other F  ST estimators, and we describe how to use these statistics to produce a rooted tree of relationships among the sampled populations in which the mean time to coalescence of haplotypes drawn from populations belonging to the same node is smaller than the mean time to coalescence of haplotypes drawn from populations belonging to different nodes. We illustrate the method by applying it to data from a recent survey of restriction site variation in the chloroplast genome of Coreopsis grandiflora.

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