scholarly journals Evolutionary inference from QST-FST comparisons: disentangling local adaptation from altitudinal gradient selection in snapdragon plants

2018 ◽  
Author(s):  
Sara Marin ◽  
Juliette Archambeau ◽  
Vincent Bonhomme ◽  
Mylène Lascoste ◽  
Benoit Pujol
Keyword(s):  
Local Adaptation ◽  
Natural Populations ◽  
Common Garden ◽  
Global Scale ◽  
Structured Populations ◽  
Adaptive Divergence ◽  
Adaptation To Climate Change ◽  
Phenotypic Differentiation ◽  
Multiple Populations ◽  
Environmental Demand

ABSTRACTPhenotypic differentiation among natural populations can be explained by natural selection or by neutral processes such as drift. There are many examples in the literature where comparing the effects of these processes on multiple populations has allowed the detection of local adaptation. However, these studies rarely identify the agents of selection. Whether population adaptive divergence is caused by local features of the environment, or by the environmental demand emerging at a more global scale, for example along altitudinal gradients, is a question that remains poorly investigated. Here, we measured neutral genetic (FST) and quantitative genetic (QST) differentiation among 13 populations of snapdragon plants (Antirrhinum majus) in a common garden experiment. We found low but significant genetic differentiation at putatively neutral markers, which supports the hypothesis of either ongoing pervasive homogenisation via gene flow between diverged populations or reproductive isolation between disconnected populations. Our results also support the hypothesis of local adaptation involving phenological, morphological, reproductive and functional traits. They also showed that phenotypic differentiation increased with altitude for traits reflecting the reproduction and the phenology of plants, thereby confirming the role of such traits in their adaptation to environmental differences associated with altitude. Our approach allowed us to identify candidate traits for the adaptation to climate change in snapdragon plants. Our findings imply that environmental conditions changing with altitude, such as the climatic envelope, influenced the adaptation of multiple populations of snapdragon plants on the top of their adaptation to local environmental features. They also have implications for the study of adaptive evolution in structured populations because they highlight the need to disentangle the adaptation of plant populations to climate envelopes and altitude from the confounding effects of selective pressures acting specifically at the local scale of a population.

scholarly journals Limited potential for adaptation to climate change in a broadly distributed marine crustacean

2011 ◽  
Vol 279 (1727) ◽  
pp. 349-356 ◽  
Author(s):  
Morgan W. Kelly ◽  
Eric Sanford ◽  
Richard K. Grosberg
Keyword(s):  
Climate Change ◽  
Local Adaptation ◽  
Thermal Tolerance ◽  
Extinction Risk ◽  
Empirical Studies ◽  
Natural Populations ◽  
Adaptation To Climate Change ◽  
Isolated Populations ◽  
Tigriopus Californicus ◽  
Standing Variation

The extent to which acclimation and genetic adaptation might buffer natural populations against climate change is largely unknown. Most models predicting biological responses to environmental change assume that species' climatic envelopes are homogeneous both in space and time. Although recent discussions have questioned this assumption, few empirical studies have characterized intraspecific patterns of genetic variation in traits directly related to environmental tolerance limits. We test the extent of such variation in the broadly distributed tidepool copepod Tigriopus californicus using laboratory rearing and selection experiments to quantify thermal tolerance and scope for adaptation in eight populations spanning more than 17° of latitude. Tigriopus californicus exhibit striking local adaptation to temperature, with less than 1 per cent of the total quantitative variance for thermal tolerance partitioned within populations. Moreover, heat-tolerant phenotypes observed in low-latitude populations cannot be achieved in high-latitude populations, either through acclimation or 10 generations of strong selection. Finally, in four populations there was no increase in thermal tolerance between generations 5 and 10 of selection, suggesting that standing variation had already been depleted. Thus, plasticity and adaptation appear to have limited capacity to buffer these isolated populations against further increases in temperature. Our results suggest that models assuming a uniform climatic envelope may greatly underestimate extinction risk in species with strong local adaptation.

scholarly journals Low but significant genetic differentiation underlies biologically meaningful phenotypic divergence in a large Atlantic salmon population

2015 ◽  
Author(s):  
Tutku Aykanat ◽  
Susan E Johnston ◽  
Panu Orell ◽  
Eero Niemelä ◽  
Jaakko Erkinaro ◽  
...  
Keyword(s):  
Life History ◽  
Genetic Differentiation ◽  
Atlantic Salmon ◽  
Genetic Divergence ◽  
Natural Populations ◽  
Structured Populations ◽  
Life History Strategies ◽  
Adaptive Divergence ◽  
Juvenile Growth ◽  
Significant Genetic Differentiation

Despite decades of research assessing the genetic structure of natural populations, the biological meaning of low yet significant genetic divergence often remains unclear due to a lack of associated phenotypic and ecological information. At the same time, structured populations with low genetic divergence and overlapping boundaries can potentially provide excellent models to study adaptation and reproductive isolation in cases where high resolution genetic markers and relevant phenotypic and life history information are available. Here, we combined SNP-based population inference with extensive phenotypic and life history data to identify potential biological mechanisms driving fine scale sub-population differentiation in Atlantic salmon (Salmo salar) from the Teno River, a major salmon river in Europe. Two sympatrically occurring sub-populations had low but significant genetic differentiation (FST = 0.018) and displayed marked differences in the distribution of life history strategies, including variation in juvenile growth rate, age at maturity and size within age classes. Large, late-maturing individuals were virtually absent from one of the two sub-populations and there were significant differences in juvenile growth rates and size-at-age after oceanic migration between individuals in the respective sub-populations. Our findings suggest that different evolutionary processes affect each sub-population and that hybridization and subsequent selection may maintain low genetic differentiation without hindering adaptive divergence.

scholarly journals Should I stay or should I go? The Ectodysplasin locus is associated with behavioural differences in threespine stickleback

2009 ◽  
Vol 5 (6) ◽  
pp. 788-791 ◽  
Author(s):  
Rowan D. H. Barrett ◽  
Tim H. Vines ◽  
Jason S. Bystriansky ◽  
Patricia M. Schulte
Keyword(s):  
Positive Selection ◽  
Local Adaptation ◽  
Morphological Traits ◽  
Genetic Basis ◽  
Natural Populations ◽  
Threespine Stickleback ◽  
Adaptive Divergence ◽  
Freshwater Habitats ◽  
Repeated Evolution ◽  
Freshwater Environments

Adaptive divergence may be facilitated if morphological and behavioural traits associated with local adaptation share the same genetic basis. It is therefore important to determine whether genes underlying adaptive morphological traits are associated with variation in behaviour in natural populations. Positive selection on low-armour alleles at the Ectodysplasin ( Eda ) locus in threespine stickleback has led to the repeated evolution of reduced armour, following freshwater colonization by fully armoured marine sticklebacks. This adaptive divergence in armour between marine and freshwater populations would be facilitated if the low allele conferred a behavioural preference for freshwater environments. We experimentally tested whether the low allele is associated with preference for freshwater by measuring the preference of each Eda genotype for freshwater versus saltwater after acclimation to either salinity. We found no association between the Eda low allele and preference for freshwater. Instead, the low allele was significantly associated with a reduced preference for the acclimation environment. This behaviour may facilitate the colonization of freshwater habitats from the sea, but could also hinder local adaptation by promoting migration of low alleles between marine and freshwater environments.

scholarly journals Mexican conifers differ in their capacity to face climate change

2017 ◽  
Vol 4 ◽  
pp. e003 ◽  
Author(s):  
Cuauhtémoc Sáenz-Romero ◽  
Maximilien Larter ◽  
Noelia González-Muñoz ◽  
Christian Wehenkel ◽  
Arnulfo Blanco-Garcia ◽  
...  
Keyword(s):  
Climate Change ◽  
Drought Stress ◽  
Natural Populations ◽  
Common Garden ◽  
Adaptation To Climate Change ◽  
Natural Habitats ◽  
Xylem Vulnerability ◽  
Adult Trees ◽  
Pinus Pseudostrobus

The recent massive dieback of forest trees due to drought stress makes assessment of the variability of physiological traits that might be critical for predicting forest response and adaptation to climate change even more urgent. We investigated xylem vulnerability to cavitation and xylem specific hydraulic conductivity in seven species of three principal conifer genera (Juniperus monticola, Juniperus deppeana, Juniperus flaccida, Pinus pseudostrobus, Pinus leiophylla, Pinus devoniana, and the endangered Picea chihuahuana) of the Mexican mountains in order to identify the species most vulnerable to future warmer and drier climates. Hydraulic traits were examined using the in situ flow centrifuge technique (Cavitron) on branches collected from adult trees of natural populations and seedlings growing in a common garden. We found evidence of significant differences in xylem safety between genera (P50: pressure inducing 50% loss of hydraulic conductance): the three juniper species exhibited low P50 values (ranging from -9.9 to -10.4 MPa), relative to the much more vulnerable pine and spruce species (P50 ranging between - 2.9 to - 3.3 MPa).  Our findings also revealed no variation in P50 between adult trees assessed in the field and seedlings growing in a common garden. We therefore propose that if, as projected, climate change makes their natural habitats much warmer and drier, populations of Mexican pines and the studied spruce will be likely to decline severely as a result of drought-stress induced cavitation, while the juniper species will survive.

scholarly journals Fine-scale local adaptation in an invasive freshwater fish has evolved in contemporary time

2013 ◽  
Vol 280 (1751) ◽  
pp. 20122327 ◽  
Author(s):  
Peter A. H. Westley ◽  
Eric J. Ward ◽  
Ian A. Fleming
Keyword(s):  
Freshwater Fish ◽  
Local Adaptation ◽  
Relative Survival ◽  
Common Garden ◽  
Population Level ◽  
Adaptive Divergence ◽  
Fine Scale ◽  
Ecological Selection ◽  
Reciprocal Transplants ◽  
Common Garden Experiments

Adaptive evolutionary change in only a few generations can increase the ability of non-native invasive species to spread, and yet adaptive divergence is rarely assessed in recently established populations. In this study, we experimentally test for evidence of fine-scale local adaptation in juvenile survival and growth among three populations of an invasive freshwater fish with reciprocal transplants and common-garden experiments. Despite intrinsic differences in habitat quality, in two of three populations we detected evidence of increased survival in ‘home’ versus ‘away’ environments with a Bayesian occupancy model fitted to mark–recapture data. We found support for the ‘local’ versus ‘foreign’ criterion of local adaptation as 14 of 15 pairwise comparisons of performance were consistent with local adaptation ( p < 0.001). Patterns in growth were less clear, though we detected evidence of location- and population-level effects. Although the agents of divergent ecological selection are not known in this system, our results combine to indicate that adaptive divergence—reflected by higher relative survival of local individuals—can occur in a small number of generations and only a few kilometres apart on the landscape.

scholarly journals Adaptive Divergence of Meiotic Recombination Rate in Ecological Speciation

2020 ◽  
Vol 12 (10) ◽  
pp. 1869-1881
Author(s):  
Swatantra Neupane ◽  
Sen Xu
Keyword(s):  
Meiotic Recombination ◽  
Recombination Rate ◽  
Natural Populations ◽  
Daphnia Pulex ◽  
Common Garden ◽  
Population Level ◽  
Directional Selection ◽  
Neutral Evolution ◽  
Adaptive Divergence ◽  
Rate Variation

Abstract Theories predict that directional selection during adaptation to a novel habitat results in elevated meiotic recombination rate. Yet the lack of population-level recombination rate data leaves this hypothesis untested in natural populations. Here, we examine the population-level recombination rate variation in two incipient ecological species, the microcrustacean Daphnia pulex (an ephemeral-pond species) and Daphnia pulicaria (a permanent-lake species). The divergence of D. pulicaria from D. pulex involved habitat shifts from pond to lake habitats as well as strong local adaptation due to directional selection. Using a novel single-sperm genotyping approach, we estimated the male-specific recombination rate of two linkage groups in multiple populations of each species in common garden experiments and identified a significantly elevated recombination rate in D. pulicaria. Most importantly, population genetic analyses show that the divergence in recombination rate between these two species is most likely due to divergent selection in distinct ecological habitats rather than neutral evolution.

scholarly journals Multivariate phenotypic divergence along an urbanization gradient

2019 ◽  
Author(s):  
James S. Santangelo ◽  
Carole Advenard ◽  
L. Ruth Rivkin ◽  
Ken A. Thompson
Keyword(s):  
Urban Areas ◽  
Natural Populations ◽  
Common Garden ◽  
Urban Environments ◽  
Floral Traits ◽  
Adaptive Divergence ◽  
Phenotypic Traits ◽  
The Novel ◽  
Urbanization Gradient ◽  
Growing Body

AbstractA growing body of evidence suggests that natural populations can evolve to better tolerate the novel environmental conditions associated with urban areas. Invariably, studies of adaptive divergence in urban areas examine only one or a few traits at a time from populations residing only at the most extreme urban and nonurban habitats. Thus, whether urbanization is driving divergence in many traits simultaneously in a manner that varies with the degree of urbanization remains unclear. To address this gap, we generated seed families of white clover (Trifolium repens) collected from 27 populations along an urbanization gradient in Toronto, Canada, and grew them up to measure multiple phenotypic traits in a common garden. Overall, urban populations had later phenology and germination, larger flowers, thinner stolons, reduced cyanogenesis, greater biomass, and were more attractive to pollinators. Pollinator observations revealed near complete turnover between urban and nonurban sites, which may explain some of the observed divergence in floral traits and phenology. Our results suggest that adaptation to urban environments involves multiple organismal traits.

scholarly journals Multivariate phenotypic divergence along an urbanization gradient

2020 ◽  
Vol 16 (9) ◽  
pp. 20200511
Author(s):  
James S. Santangelo ◽  
L. Ruth Rivkin ◽  
Carole Advenard ◽  
Ken A. Thompson
Keyword(s):  
Urban Areas ◽  
Natural Populations ◽  
Common Garden ◽  
Urban Environments ◽  
Adaptive Divergence ◽  
Phenotypic Traits ◽  
The Novel ◽  
Multiple Traits ◽  
Urbanization Gradient ◽  
Urban Sites

Evidence suggests that natural populations can evolve to better tolerate the novel environmental conditions associated with urban areas. Studies of adaptive divergence in urban areas often examine one or a few traits at a time from populations residing only at the most extreme urban and nonurban habitats. Thus, whether urbanization drives divergence in many traits simultaneously in a manner that varies with the degree of urbanization remains unclear. To address this gap, we generated seed families of white clover ( Trifolium repens ) collected from 27 populations along an urbanization gradient in Toronto, Canada, grew them in a common garden, and measured 14 phenotypic traits. Families from urban sites had evolved later phenology and germination, larger flowers, thinner stolons, reduced cyanogenesis, greater biomass and greater seed set. Pollinator observations revealed near-complete turnover of pollinator morphological groups along the urbanization gradient, which may explain some of the observed divergences in floral traits and phenology. Our results suggest that adaptation to urban environments involves multiple traits.

scholarly journals Global adaptation confounds the search for local adaptation

2019 ◽  
Author(s):  
Tom R. Booker ◽  
Sam Yeaman ◽  
Michael C. Whitlock
Keyword(s):  
Genetic Differentiation ◽  
Local Adaptation ◽  
Natural Populations ◽  
Wide Distribution ◽  
Structured Populations ◽  
Substantial Contribution ◽  
Beneficial Mutations ◽  
Genome Wide ◽  
Spatially Varying ◽  
Spatially Varying Selection

AbstractSpatially varying selection promotes variance in allele frequencies, increasing genetic differentiation between the demes of a metapopulation. For that reason, outliers in the genome wide distribution of summary statistics measuring genetic differentiation, such as FST, are often interpreted as evidence for alleles which contribute to local adaptation. However, in spatially structured populations, the spread of beneficial mutations with spatially uniform effects can also induce transient genetic differentiation and numerous theoretical studies have suggested that species-wide, or global, adaptation makes a substantial contribution to molecular evolution. In this study, we ask whether such global adaptation affects the genome-wide distribution of FST and generates statistical outliers which could be mistaken for local adaptation. Using forward-in-time population genetic simulations assuming parameters for the rate and strength of beneficial mutations similar to those that have been estimated for natural populations, we show the spread of globally beneficial in parapatric populations can readily generate FST outliers, which may be misinterpreted as evidence for local adaptation. The spread of beneficial mutations causes selective sweeps at flanking sites, so the effects of global versus local adaptation may be distinguished by examining patterns of nucleotide diversity along with FST. Our study suggests that global adaptation should be considered in the interpretation of genome-scan results and the design of future studies aimed at understanding the genetic basis of local adaptation.

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