scholarly journals Selection on early survival does not explain germination rate clines in Mimulus cardinalis (Phrymaceae)

2021 ◽  
Author(s):  
Christopher D Muir ◽  
Courtney L Van Den Elzen ◽  
Amy Lauren Angert
Keyword(s):  
Local Adaptation ◽  
Genetic Variance ◽  
Environmental Gradients ◽  
Germination Rate ◽  
Population Level ◽  
Genotypic Selection ◽  
Early Survival ◽  
Non Gaussian ◽  
Log Normal ◽  
Future Work

Premise Many traits covary with environmental gradients to form phenotypic clines. While local adaptation to the environment can generate phenotypic clines, other nonadaptive processes may also. If local adaptation causes phenotypic clines, then the direction of genotypic selection on traits should shift from one end of the cline to the other. Traditionally genotypic selection on non-Gaussian traits like germination rate have been hampered because it is challenging to measure their genetic variance. Methods Here we used quantitative genetics and reciprocal transplants to test whether a previously discovered cline in germination rate showed additional signatures of adaptation in the scarlet monkeyflower (Mimulus cardinalis). We measured genotypic and population level covariation between germination rate and early survival, a component of fitness. We developed a novel discrete log-normal model to estimate genetic variance in germination rate. Results Contrary to our adaptive hypothesis, we found no evidence that genetic variation in germination rate contributed to variation in early survival. Across populations, southern populations in both gardens germinated earlier and survived more. Conclusions Southern populations have higher early survival but this is not caused by faster germination. This pattern is consistent with nonadaptive forces driving the phenotypic cline in germination rate, but future work will need to assess whether there is selection at other life stages. The statistical framework should help expand quantitative genetic analyses for other waiting-time traits.

scholarly journals The Evolution of Gambling-Related Harm Measurement: Lessons from the Last Decade

2021 ◽  
Vol 18 (9) ◽  
pp. 4395
Author(s):  
Matthew Browne ◽  
Vijay Rawat ◽  
Catherine Tulloch ◽  
Cailem Murray-Boyle ◽  
Matthew Rockloff
Keyword(s):  
Public Health ◽  
Population Level ◽  
Health Utility ◽  
Health And Wellbeing ◽  
Recent Developments ◽  
Psychometric Evidence ◽  
Future Work ◽  
Utility Metrics ◽  
Gambling Harms ◽  
Related Harm

Jurisdictions around the world have a self-declared mandate to reduce gambling-related harm. However, historically, this concept has suffered from poor conceptualisation and operationalisation. However, recent years have seen swift advances in measuring gambling harm, based on the principle of it being a quantifiable decrement to the health and wellbeing of the gambler and those connected to them. This review takes stock of the background and recent developments in harm assessment and summarises recent research that has validated and applied the Short Gambling Harms Screen and related instruments. We recommend that future work builds upon the considerable psychometric evidence accumulated for the feasibility of direct elicitation of harmful consequences. We also advocate for grounding harms measures with respect to scalar changes to public health utility metrics. Such an approach will avoid misleading pseudo-clinical categorisations, provide accurate population-level summaries of where the burden of harm is carried, and serve to integrate gambling research with the broader field of public health.

scholarly journals Nanopore amplicon sequencing reveals molecular convergence and local adaptation of opsin genes

2020 ◽  
Author(s):  
Katherine M. Eaton ◽  
Moisés A. Bernal ◽  
Nathan J.C. Backenstose ◽  
Trevor J. Krabbenhoft
Keyword(s):  
Local Adaptation ◽  
Environmental Gradients ◽  
Parallel Evolution ◽  
Amplicon Sequencing ◽  
Species Flock ◽  
Closely Related Species ◽  
Oxford Nanopore ◽  
Opsin Genes ◽  
Potential Case ◽  
Species Specific

AbstractLocal adaptation can drive diversification of closely related species across environmental gradients and promote convergence of distantly related taxa that experience similar conditions. We examined a potential case of adaptation to novel visual environments in a species flock (Great Lakes salmonids, genus Coregonus) using a new amplicon genotyping protocol on the Oxford Nanopore Flongle. Five visual opsin genes were amplified for individuals of C. artedi, C. hoyi, C. kiyi, and C. zenithicus. Comparisons revealed species-specific differences in the coding sequence of rhodopsin (Tyr261Phe substitution), suggesting local adaptation by C. kiyi to the blue-shifted depths of Lake Superior. Parallel evolution and “toggling” at this amino acid residue has occurred several times across the fish tree of life, resulting in identical changes to the visual systems of distantly related taxa across replicated environmental gradients. Our results suggest that ecological differences and local adaptation to distinct visual environments are strong drivers of both evolutionary parallelism and diversification.

scholarly journals Do Differences in Latitudinal Distributions of Species and Organelle Haplotypes Reflect Thermal Reaction Norms Within the Emiliania/Gephyrocapsa Complex?

2021 ◽  
Vol 8 ◽  
Author(s):  
Peter von Dassow ◽  
Paula Valentina Muñoz Farías ◽  
Sarah Pinon ◽  
Esther Velasco-Senovilla ◽  
Simon Anguita-Salinas
Keyword(s):  
Local Adaptation ◽  
Coastal Upwelling ◽  
Environmental Gradients ◽  
Reaction Norm ◽  
Emiliania Huxleyi ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Thermal Niche ◽  
Significant Difference ◽  
The Difference

The cosmopolitan phytoplankter Emiliania huxleyi contrasts with its closest relatives that are restricted to narrower latitudinal bands, making it interesting for exploring how alternative outcomes in phytoplankton range distributions arise. Mitochondrial and chloroplast haplogroups within E. huxleyi are shared with their closest relatives: Some E. huxleyi share organelle haplogroups with Gephyrocapsa parvula and G. ericsonii which inhabit lower latitudes, while other E. huxleyi share organelle haplogroups with G. muellerae, which inhabit high latitudes. We investigated whether the phylogeny of E. huxleyi organelles reflects environmental gradients, focusing on the Southeast Pacific where the different haplogroups and species co-occur. There was a high congruence between mitochondrial and chloroplast haplogroups within E. huxleyi. Haplogroup II of E. huxleyi is negatively associated with cooler less saline waters, compared to haplogroup I, both when analyzed globally and across temporal variability at the small special scale of a center of coastal upwelling at 30° S. A new mitochondrial haplogroup Ib detected in coastal Chile was associated with warmer waters. In an experiment focused on inter-species comparisons, laboratory-determined thermal reaction norms were consistent with latitudinal/thermal distributions of species, with G. oceanica exhibiting warm thermal optima and tolerance and G. muellerae exhibiting cooler thermal optima and tolerances. Emiliania huxleyi haplogroups I and II tended to exhibit a wider thermal niche compared to the other Gephyrocapsa, but no differences among haplogroups within E. huxleyi were found. A second experiment, controlling for local adaptation and time in culture, found a significant difference between E. huxleyi haplogroups. The difference between I and II was of the expected sign, but not the difference between I and Ib. The differences were small (≤1°C) compared to differences reported previously within E. huxleyi by local adaptation and even in-culture evolution. Haplogroup Ib showed a narrower thermal niche. The cosmopolitanism of E. huxleyi might result from both wide-spread generalist phenotypes and specialist phenotypes, as well as a capacity for local adaptation. Thermal reaction norm differences can well explain the species distributions but poorly explain distributions among mitochondrial haplogroups within E. huxleyi. Perhaps organelle haplogroup distributions reflect historical rather than selective processes.

scholarly journals Evolutionary origins for ecological patterns in space

2020 ◽  
Vol 117 (30) ◽  
pp. 17482-17490 ◽  
Author(s):  
Mark C. Urban ◽  
Sharon Y. Strauss ◽  
Fanie Pelletier ◽  
Eric P. Palkovacs ◽  
Mathew A. Leibold ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Keystone Species ◽  
Future Research ◽  
Evolutionary Divergence ◽  
Patch Selection ◽  
Fully Integrated ◽  
Evolutionary Origins ◽  
Ecological Patterns

Historically, many biologists assumed that evolution and ecology acted independently because evolution occurred over distances too great to influence most ecological patterns. Today, evidence indicates that evolution can operate over a range of spatial scales, including fine spatial scales. Thus, evolutionary divergence across space might frequently interact with the mechanisms that also determine spatial ecological patterns. Here, we synthesize insights from 500 eco-evolutionary studies and develop a predictive framework that seeks to understand whether and when evolution amplifies, dampens, or creates ecological patterns. We demonstrate that local adaptation can alter everything from spatial variation in population abundances to ecosystem properties. We uncover 14 mechanisms that can mediate the outcome of evolution on spatial ecological patterns. Sometimes, evolution amplifies environmental variation, especially when selection enhances resource uptake or patch selection. The local evolution of foundation or keystone species can create ecological patterns where none existed originally. However, most often, we find that evolution dampens existing environmental gradients, because local adaptation evens out fitness across environments and thus counteracts the variation in associated ecological patterns. Consequently, evolution generally smooths out the underlying heterogeneity in nature, making the world appear less ragged than it would be in the absence of evolution. We end by highlighting the future research needed to inform a fully integrated and predictive biology that accounts for eco-evolutionary interactions in both space and time.

scholarly journals Parasite induced mortality is context dependent in Atlantic salmon: insights from an individual-based model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Knut Wiik Vollset
Keyword(s):  
Atlantic Salmon ◽  
Environmental Gradients ◽  
Population Level ◽  
Relative Effect ◽  
Host Population ◽  
Sea Lice ◽  
Fish Farms ◽  
Individual Based Model ◽  
Parasite Infestation ◽  
The Impact

AbstractAn individual-based model was parameterized to explore the impact of a crustacean ectoparasite (sea louse, Lepeophtheirus salmonis & Caligus spp.) on migrating Atlantic salmon smolt. The model explores how environmental and intrinsic factors can modulate the effect of sea lice on survival, growth and maturation of Atlantic salmon at sea. Relative to other effects, the parasite infestation pressure from fish farms and the encounter process emerge as the most important parameters. Although small variations in parasite-induced mortality may be masked by variable environmental effects, episodes of high infestation pressure from fish farms should be observable in wild populations of Atlantic salmon if laboratory studies accurately reflect the physiological effects of sea lice. Increases in temperature in the model negatively influenced fish survival by affecting the development time of the parasite at a rate that was not compensated for by the growth of the host. Discharge from rivers was parameterized to increase migration speed and influenced parasite induced mortality by decreasing time spent in areas with increased infestation pressure. Initial size and growth of the host was inversely related to the impact of the parasite because of size-dependent parasite-induced mortality in the early phase of migration. Overall, the model illustrates how environmental factors modulate effects on the host population by impacting either the parasite load or the relative effect of the parasite. The results suggest that linking population-level effects to parasite infestation pressure across climatic and environmental gradients may be challenging without correctly accounting for these effects.

scholarly journals QTL × environment interactions underlie adaptive divergence in switchgrass across a large latitudinal gradient

2019 ◽  
Vol 116 (26) ◽  
pp. 12933-12941 ◽  
Author(s):  
David B. Lowry ◽  
John T. Lovell ◽  
Li Zhang ◽  
Jason Bonnette ◽  
Philip A. Fay ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Panicum Virgatum ◽  
Environmental Gradients ◽  
Adaptive Divergence ◽  
Multiple Loci ◽  
Trade Offs ◽  
Locally Adaptive ◽  
Trait Locus ◽  
Benefits And Costs ◽  
Transplant Experiments

Local adaptation is the process by which natural selection drives adaptive phenotypic divergence across environmental gradients. Theory suggests that local adaptation results from genetic trade-offs at individual genetic loci, where adaptation to one set of environmental conditions results in a cost to fitness in alternative environments. However, the degree to which there are costs associated with local adaptation is poorly understood because most of these experiments rely on two-site reciprocal transplant experiments. Here, we quantify the benefits and costs of locally adaptive loci across 17° of latitude in a four-grandparent outbred mapping population in outcrossing switchgrass (Panicum virgatumL.), an emerging biofuel crop and dominant tallgrass species. We conducted quantitative trait locus (QTL) mapping across 10 sites, ranging from Texas to South Dakota. This analysis revealed that beneficial biomass (fitness) QTL generally incur minimal costs when transplanted to other field sites distributed over a large climatic gradient over the 2 y of our study. Therefore, locally advantageous alleles could potentially be combined across multiple loci through breeding to create high-yielding regionally adapted cultivars.

scholarly journals Estimation of Genetic Variance in Fitness, and Inference of Adaptation, When Fitness Follows a Log-Normal Distribution

2019 ◽  
Vol 110 (4) ◽  
pp. 383-395 ◽  
Author(s):  
Timothée Bonnet ◽  
Michael B Morrissey ◽  
Loeske E B Kruuk
Keyword(s):  
Natural Selection ◽  
Animal Models ◽  
Normal Distribution ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Relative Fitness ◽  
Parameter Estimates ◽  
Log Normal ◽  
Change In Mean ◽  
Log Normal Distribution

AbstractAdditive genetic variance in relative fitness (σA2(w)) is arguably the most important evolutionary parameter in a population because, by Fisher’s fundamental theorem of natural selection (FTNS; Fisher RA. 1930. The genetical theory of natural selection. 1st ed. Oxford: Clarendon Press), it represents the rate of adaptive evolution. However, to date, there are few estimates of σA2(w) in natural populations. Moreover, most of the available estimates rely on Gaussian assumptions inappropriate for fitness data, with unclear consequences. “Generalized linear animal models” (GLAMs) tend to be more appropriate for fitness data, but they estimate parameters on a transformed (“latent”) scale that is not directly interpretable for inferences on the data scale. Here we exploit the latest theoretical developments to clarify how best to estimate quantitative genetic parameters for fitness. Specifically, we use computer simulations to confirm a recently developed analog of the FTNS in the case when expected fitness follows a log-normal distribution. In this situation, the additive genetic variance in absolute fitness on the latent log-scale (σA2(l)) equals (σA2(w)) on the data scale, which is the rate of adaptation within a generation. However, due to inheritance distortion, the change in mean relative fitness between generations exceeds σA2(l) and equals (exp⁡(σA2(l))−1). We illustrate why the heritability of fitness is generally low and is not a good measure of the rate of adaptation. Finally, we explore how well the relevant parameters can be estimated by animal models, comparing Gaussian models with Poisson GLAMs. Our results illustrate 1) the correspondence between quantitative genetics and population dynamics encapsulated in the FTNS and its log-normal-analog and 2) the appropriate interpretation of GLAM parameter estimates.

scholarly journals Evaluation of genetic isolation within an island flora reveals unusually widespread local adaptation and supports sympatric speciation

2014 ◽  
Vol 369 (1648) ◽  
pp. 20130342 ◽  
Author(s):  
Alexander S. T. Papadopulos ◽  
Maria Kaye ◽  
Céline Devaux ◽  
Helen Hipperson ◽  
Jackie Lighten ◽  
...  
Keyword(s):  
Gene Flow ◽  
Local Adaptation ◽  
Plant Species ◽  
Environmental Gradients ◽  
Isolation By Distance ◽  
Model Averaging ◽  
Dispersal Limitation ◽  
Population Divergence ◽  
Environmental Pressures ◽  
Isolation By Environment

It is now recognized that speciation can proceed even when divergent natural selection is opposed by gene flow. Understanding the extent to which environmental gradients and geographical distance can limit gene flow within species can shed light on the relative roles of selection and dispersal limitation during the early stages of population divergence and speciation. On the remote Lord Howe Island (Australia), ecological speciation with gene flow is thought to have taken place in several plant genera. The aim of this study was to establish the contributions of isolation by environment (IBE) and isolation by community (IBC) to the genetic structure of 19 plant species, from a number of distantly related families, which have been subjected to similar environmental pressures over comparable time scales. We applied an individual-based, multivariate, model averaging approach to quantify IBE and IBC, while controlling for isolation by distance (IBD). Our analyses demonstrated that all species experienced some degree of ecologically driven isolation, whereas only 12 of 19 species were subjected to IBD. The prevalence of IBE within these plant species indicates that divergent selection in plants frequently produces local adaptation and supports hypotheses that ecological divergence can drive speciation in sympatry.

scholarly journals Toward a synthetic understanding of the role of phenology in ecology and evolution

2010 ◽  
Vol 365 (1555) ◽  
pp. 3101-3112 ◽  
Author(s):  
Jessica Forrest ◽  
Abraham J. Miller-Rushing
Keyword(s):  
Climate Change ◽  
Population Level ◽  
Annual Cycles ◽  
Biological Phenomena ◽  
Ecosystem Level ◽  
Modelling Techniques ◽  
Evolutionary Consequences ◽  
Future Work ◽  
The Relationship

Phenology affects nearly all aspects of ecology and evolution. Virtually all biological phenomena—from individual physiology to interspecific relationships to global nutrient fluxes—have annual cycles and are influenced by the timing of abiotic events. Recent years have seen a surge of interest in this topic, as an increasing number of studies document phenological responses to climate change. Much recent research has addressed the genetic controls on phenology, modelling techniques and ecosystem-level and evolutionary consequences of phenological change. To date, however, these efforts have tended to proceed independently. Here, we bring together some of these disparate lines of inquiry to clarify vocabulary, facilitate comparisons among habitat types and promote the integration of ideas and methodologies across different disciplines and scales. We discuss the relationship between phenology and life history, the distinction between organismal- and population-level perspectives on phenology and the influence of phenology on evolutionary processes, communities and ecosystems. Future work should focus on linking ecological and physiological aspects of phenology, understanding the demographic effects of phenological change and explicitly accounting for seasonality and phenology in forecasts of ecological and evolutionary responses to climate change.

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