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Context: Lates calcarifer is a widespread Indo-Pacific fish that is important in aquaculture, recreational and commercial fisheries. Genetic divergences from different data sources and sampling schemes have been reported. Aims: To conduct phylogenetic and population genetic analyses from a geographically and phylogenetically representative data set to identify hierarchical divisions within L. calcarifer. We further test the evolutionary significance of genetic units in terms of signatures of adaptation. Methods: Using a whole-genome sequence data set of 61 fish, including an outgroup, we conducted phylogenetic and population genetic analyses. We also generated measures of fixation index (F st), nucleotide diversity (π) and Tajima's D (D). Key results: We identified three main lineages of L. calcarifer , corresponding to the Indian subcontinent, South-east Asia and Australasia. Subdivision within each of the three main lineages was also identified and characterised. Adaptively significant differences are indicated within and among the three main lineages. Conclusions: L. calcarifer exhibits genetic divergences at different levels that originate before and during the Pleistocene. These divergences are associated with adaptive divergence but unclear phenotypic changes. Implications: This study has highlighted the need for comprehensive sampling and integrative study of genotypes and phenotypes across the range of L. calcarifer. Asian sea bass, or barramundi, is a widespread fish widely propagated and highly sought after for food and recreation. We found that the Asian sea bass and barramundi lineage contains three main genetic lineages with numerous subdivisions, and that these divisions are linked to adaptive changes and may be considered evolutionarily significant. These findings indicate diversity within Asian sea bass and barramundi that may be useful for both conservation and exploitation. [ABSTRACT FROM AUTHOR]

As climate changes, understanding the genetic basis of local adaptation in plants becomes an ever more pressing issue. Combining genotype-environment association (GEA) with genotype-phenotype association (GPA) analysis has an exciting potential to uncover the genetic basis of environmental responses. We use these approaches to identify genetic variants linked to local adaptation to drought in Pinus ponderosa. Over 4 million Single Nucleotide Polymorphisms (SNPs) were identified using 223 individuals from across the Sierra Nevada of California. 927,740 (22.3%) SNPs were retained after filtering for proximity to genes and used in our association analyses. We found 1374 associated with five major climate variables, with the largest number (1151) associated with April 1st snowpack. We also conducted a greenhouse study with various drought-tolerance traits measured in first-year seedlings of a subset of the genotyped trees grown in the greenhouse. 796 SNPs were associated with control-condition trait values, while 1149 were associated with responsiveness of these traits to drought. While no individual SNPs were associated with both the environmental variables and the measured traits, several annotated genes were associated with both, particularly those involved in cell wall formation, biotic and abiotic stress responses, and ubiquitination. However, the functions of many of the associated genes have not yet been determined due to the lack of gene annotation information for conifers. Future studies are needed to assess the developmental roles and ecological significance of these unknown genes.

Animals are strongly connected to the environments they live in and may become adapted to local environments. Examining genetic–environment associations of key indicator species, like seabirds, provides greater insights into the forces that drive evolution in marine systems. Here we examined a RADseq dataset of 19,213 SNPs for 99 rhinoceros auklets (Cerorhinca monocerata) from five western Pacific and 10 eastern Pacific breeding colonies. We used partial redundancy analyses to identify candidate adaptive loci and to quantify the effects of environmental variation on population genetic structure. We identified 262 candidate adaptive loci, which accounted for 3.0% of the observed genetic variation among western Pacific and eastern Pacific breeding colonies. Genetic variation was more strongly associated with pH and maximum current velocity, than maximum sea surface temperature. Genetic–environment associations explain genetic differences between western and eastern Pacific populations; however, genetic variation within the western and eastern Pacific Ocean populations appears to follow a pattern of isolation‐by‐distance. This study represents a first to quantify the relationship between environmental and genetic variation for this widely distributed marine species and provides greater insights into the evolutionary forces that act on marine species. [ABSTRACT FROM AUTHOR]

Migration is a complex phenotypic trait with some species containing migratory and nonmigratory individuals. Such life history variation may be attributed in part to plasticity, epigenetics, or genetics. Although considered semianadromous, recent studies using otolith geochemistry have revealed life history variation within the critically endangered Delta Smelt. Broadly categorizable as migratory or freshwater residents, we examined Restriction site Associated DNA sequencing data to test for a relationship between genetic variation and migratory behaviors. As previously shown, we found no evidence for neutral population genetic structure within Delta Smelt; however, we found significant evidence for associations between genetic variants and life history phenotypes. Furthermore, discriminant analysis of principal components, hierarchical clustering, and machine learning resulted in accurate assignment of fish into the freshwater resident or migratory classes based on their genotypes. These results suggest the presence of adaptive genetic variants relating to life history variation within a panmictic population. Mechanisms that may lead to this observation are genotype dependent habitat choice and spatially variable selection, both of which could operate each generation and are not exclusive. Given that the population of cultured Delta Smelt are being used as a refugial population for conservation, as a supply for wild population supplementation, and currently represent the majority of all living individuals of this species, we recommend that the hatchery management strategy consider the frequencies of life history-associated alleles and how to maintain this important aspect of Delta Smelt biological variation while under captive propagation.

Genetic tools for wildlife monitoring can provide valuable information on spatiotemporal population trends and connectivity, particularly in systems experiencing rapid environmental change. Multiplexed targeted amplicon sequencing techniques, such as genotyping‐in‐thousands by sequencing (GT‐seq), can provide cost‐effective approaches for collecting genetic data from low‐quality and quantity DNA samples, making them potentially useful for long‐term wildlife monitoring using non‐invasive and archival samples. Here, we developed a GT‐seq panel as a potential monitoring tool for the American pika (Ochotona princeps) and evaluated its performance when applied to traditional, non‐invasive, and archival samples, respectively. Specifically, we optimized a GT‐seq panel (307 single nucleotide polymorphisms (SNPs)) that included neutral, sex‐associated, and putatively adaptive SNPs using contemporary tissue samples (n = 77) from the Northern Rocky Mountains lineage of American pikas. The panel demonstrated high genotyping success (94.7%), low genotyping error (0.001%), and excellent performance identifying individuals, sex, relatedness, and population structure. We subsequently applied the GT‐seq panel to archival tissue (n = 17) and contemporary fecal pellet samples (n = 129) collected within the Canadian Rocky Mountains to evaluate its effectiveness. Although the panel demonstrated high efficacy with archival tissue samples (90.5% genotyping success, 0.0% genotyping error), this was not the case for the fecal pellet samples (79.7% genotyping success, 28.4% genotyping error) likely due to the exceptionally low quality/quantity of recovered DNA using the approaches implemented. Overall, our study reinforced GT‐seq as an effective tool using contemporary and archival tissue samples, providing future opportunities for temporal applications using historical specimens. Our results further highlight the need for additional optimization of sample and genetic data collection techniques prior to broader‐scale implementation of a non‐invasive genetic monitoring tool for American pikas. [ABSTRACT FROM AUTHOR]

The greater kudu (Tragelaphus strepsiceros) is widespread throughout South Africa and occurs in higher densities in the north-eastern regions, with isolated populations in the Eastern Cape Province and in the Kimberley area in the Northern Cape Province. This study aimed to assess the phylogeographic structure of regional South African greater kudu groups, based on neutral mitochondrial DNA regions as well as adaptive variation. A total of 116 kudu were sampled from across the South African distribution range, separated by geographic features and distance, from six South African provinces. Sampling was mainly based on skin samples collected from taxidermists. Genetic diversity and differentiation were quantified using sequence data from the mitochondrial control region (mtDNA CR) and the heat shock protein subunit 5 (HSPA5) gene. Short tandem repeat (STR) sequences were identified at the 3′-UTR of the bone morphogenetic protein 4 (BMP4) gene and used for downstream analyses. Twenty-six haplotypes were identified from the CR dataset, three for the HSPA5 region, and 14 alleles were identified for the BMP4 STR. The CR phylogenetic analyses identified two distinct genetic clades representing an Eastern and Western group respectively. Molecular divergence dating identified the most recent common ancestor of the Eastern and Western South African kudu clades as older (2.237 Mya) than some well-known African antelope species. This result was consistent with the HSPA5 and BMP4 results. Environmental selective pressures, such as rainfall and ambient temperature, were also identified as possible driving forces for evolution at the HSPA5 gene region. Overall, these results can provide support for future management decisions to ensure the conservation of natural patterns of diversity in this majestic antelope species in South Africa. [ABSTRACT FROM AUTHOR]

Migration is a complex phenotypic trait with some species containing migratory and nonmigratory individuals. Such life history variation may be attributed in part to plasticity, epigenetics, or genetics. Although considered semianadromous, recent studies using otolith geochemistry have revealed life history variation within the critically endangered Delta Smelt. Broadly categorizable as migratory or freshwater residents, we examined Restriction site Associated DNA sequencing data to test for a relationship between genetic variation and migratory behaviors. As previously shown, we found no evidence for neutral population genetic structure within Delta Smelt; however, we found significant evidence for associations between genetic variants and life history phenotypes. Furthermore, discriminant analysis of principal components, hierarchical clustering, and machine learning resulted in accurate assignment of fish into the freshwater resident or migratory classes based on their genotypes. These results suggest the presence of adaptive genetic variants relating to life history variation within a panmictic population. Mechanisms that may lead to this observation are genotype dependent habitat choice and spatially variable selection, both of which could operate each generation and are not exclusive. Given that the population of cultured Delta Smelt are being used as a refugial population for conservation, as a supply for wild population supplementation, and currently represent the majority of all living individuals of this species, we recommend that the hatchery management strategy consider the frequencies of life history-associated alleles and how to maintain this important aspect of Delta Smelt biological variation while under captive propagation. [ABSTRACT FROM AUTHOR]

Abstract Objectives Efforts to restore tropical peat swamp forests in Indonesia face huge challenges of potential failures due to socio-economic factors and ecological dynamics attributed to lack of knowledge on the adaptive mechanisms of potential tree species such as Kapur (Dryobalanops aromatica C.F.Gaertn Syn. Dryobalanops sumatrensis J.F. Gmelin A.J.G.H Kostermans). This species is a multi-purpose tree that, commonly grows in mineral soils, but also in peat swamp as previously reported, which raised a fundamental question regarding the molecular mechanism of this adaptation. Therefore, a dataset was created aiming to detect candidates of adaptive genes in D. aromatica seedlings, cultivated in two contrasting potting media, namely mineral soil and peat media, based on RNA Sequencing Transcriptome Analysis. Data description The RNA transcriptome data of D. aromatica’s seedlings derived from young leaves of three one-year-old seedlings, raised in each dry mineral soil media and peat media, were generated by using Illumina HiSeq 4000 platform in NovogenAIT, Singapore. The acquired data, as the first transcriptome dataset for D. aromatica, is of a great importance in understanding molecular mechanism and responses of the involved genes of D. aromatica to the contrasting, growing potting media conditions that could also be useful to generate molecular markers.

Landscape genomics identifies how spatial and environmental factors structure the amount and distribution of genetic variation among populations. Landscape genomic analyses have been applied across diverse taxonomic groups and ecological settings, and are increasingly used to analyse datasets composed of large numbers of genomic markers and multiple environmental predictors.It is in this context that multivariate methods show their strengths. Redundancy analysis (RDA) is a constrained ordination that, in a landscape genomics framework, models linear relationships among environment predictors and genomic variation, effectively identifying covarying allele frequencies associated with the multivariate environment. RDA can be used at both individual and population levels, can include covariates to account for confounding factors and can be used to directly infer genotype–environment associations on the landscape. The modelling of both multivariate response and explanatory variables allows RDA to accommodate the genomic and environmental complexity found in nature, producing a powerful and efficient tool for landscape genomics.In this review, we outline the diverse uses of RDA in landscape genomics, including variable selection, variance partitioning, genotype–environment associations, and the calculation of adaptive indices and genomic offset. To illustrate these applications, we use a published dataset for lodgepole pine that includes genomic, phenotypic and environmental data. We provide an introduction to the statistical basis of RDA, a tutorial on its use and interpretation in landscape genomics applications, discuss limitations and provide guidelines to avoid misuse.This review and associated tutorial provide a comprehensive resource to the landscape genomics community to improve understanding of RDA as a modelling framework, and encourage the appropriate use of RDA across diverse landscape genomics applications. RDA is truly a Swiss Army Knife for landscape genomics: a multipurpose, adaptable and versatile approach to identifying, evaluating and forecasting relationships between genetic and environmental variation. [ABSTRACT FROM AUTHOR]

Abstract Genetic diversity is essential for populations to adapt to changing environments. Measures of genetic diversity are often based on selectively neutral markers, such as microsatellites. Genetic diversity to guide conservation management, however, is better reflected by adaptive markers, including genes of the major histocompatibility complex (MHC). Our aim was to assess MHC and neutral genetic diversity in two contrasting bottlenose dolphin (Tursiops aduncus) populations in Western Australia—one apparently viable population with high reproductive output (Shark Bay) and one with lower reproductive output that was forecast to decline (Bunbury). We assessed genetic variation in the two populations by sequencing the MHC class II DQB, which encompasses the functionally important peptide binding regions (PBR). Neutral genetic diversity was assessed by genotyping twenty‐three microsatellite loci. We confirmed that MHC is an adaptive marker in both populations. Overall, the Shark Bay population exhibited greater MHC diversity than the Bunbury population—for example, it displayed greater MHC nucleotide diversity. In contrast, the difference in microsatellite diversity between the two populations was comparatively low. Our findings are consistent with the hypothesis that viable populations typically display greater genetic diversity than less viable populations. The results also suggest that MHC variation is more closely associated with population viability than neutral genetic variation. Although the inferences from our findings are limited, because we only compared two populations, our results add to a growing number of studies that highlight the usefulness of MHC as a potentially suitable genetic marker for animal conservation. The Shark Bay population, which carries greater adaptive genetic diversity than the Bunbury population, is thus likely more robust to natural or human‐induced changes to the coastal ecosystem it inhabits.

Lake trout stocks in the Great Lakes basin show variability in the relationship between a thiamine-dependent early mortality syndrome (EMS) and egg thiamine (B1) concentration but the reasons are unclear. EMS has been linked to a diet of alewives and their high thiaminase activity. We examined the relationship among four alewife-dependent B1-deficient lake trout stocks, and determined B1 utilization rates for three of these stocks, and a non-alewife-dependent B1-replete stock. Although the EMS-B1 relationship was similar between an inland lake stock and Lake Ontario, there was almost no EMS in lake trout from two Finger Lakes: Cayuga (CL) and Seneca (SL) Lakes. B1 utilization rate for the SL stock was lower than for all other stocks. Similarity in the EMS-B1 relationship (CL, SL) and reduced thiamine utilization in the SL stock suggests that Finger Lakes lake trout are better able to cope with the low egg thiamine concentration resulting from an alewife diet. Reduced thiamine utilization during the embryonic stage, possibly as a result of adaptive genetic variation, may result in a greater contribution by Seneca Lake strain lake trout to wild lake trout populations in the Great Lakes. [ABSTRACT FROM AUTHOR]

The availability of genomic data for an increasing number of species makes it possible to incorporate evolutionary processes into conservation plans. Recent studies show how genetic data can inform spatial conservation prioritization (SCP), but they focus on metrics of diversity and distinctness derived primarily from neutral genetic data sets. Identifying adaptive genetic markers can provide important information regarding the capacity for populations to adapt to environmental change. Yet, the effect of including metrics based on adaptive genomic data into SCP in comparison to more widely used neutral genetic metrics has not been explored. We used existing genomic data on a commercially exploited species, the giant California sea cucumber (Parastichopus californicus), to perform SCP for the coastal region of British Columbia (BC), Canada. Using a RAD‐seq data set for 717 P. californicus individuals across 24 sampling locations, we identified putatively adaptive (i.e., candidate) single nucleotide polymorphisms (SNPs) based on genotype–environment associations with seafloor temperature. We calculated various metrics for both neutral and candidate SNPs and compared SCP outcomes with independent metrics and combinations of metrics. Priority areas varied depending on whether neutral or candidate SNPs were used and on the specific metric used. For example, targeting sites with a high frequency of warm‐temperature‐associated alleles to support persistence under future warming prioritized areas in the southern coastal region. In contrast, targeting sites with high expected heterozygosity at candidate loci to support persistence under future environmental uncertainty prioritized areas in the north. When combining metrics, all scenarios generated intermediate solutions, protecting sites that span latitudinal and thermal gradients. Our results demonstrate that distinguishing between neutral and adaptive markers can affect conservation solutions and emphasize the importance of defining objectives when choosing among various genomic metrics for SCP. Article impact statement: Genomic metrics derived from neutral and adaptive genomic data result in different spatial conservation prioritization solutions. [ABSTRACT FROM AUTHOR]

When prioritizing populations for conservation of a given species, it is unclear whether the distribution of standing genetic variation can be used as a suitable proxy for the distribution of useful adaptive genetic variation. We tested whether using genome-wide and putatively adaptive genetic variation give similar prioritization results. We identified adaptive loci via their association with either environmental factors or phenotypic traits using two genomic data sets: yellow warblers (Setophaga petechia) across North America and lodgepole pines (Pinus contorta) in western Canada. We measured pairwise differentiation among populations using a principal components analysis and used a phylogenetic approach (NeighborNet networks) coupled with a measure of evolutionary distinctiveness (Shapley value) to attribute a priority rank to each population. Overall, we found that prioritization rankings using adaptive variation alone were not significantly divergent from rankings based on genome-wide genetic variation. Our testing framework might be of immediate use to conservation practitioners collecting next-generation sequencing data, and we call for further investigation in other species. Our results suggest that we may not need to pursue the contingent step of identifying adaptive variation in species of concern before prioritizing populations, i.e. a naive approach of using genome-wide genetic variation might be a suitable proxy for identifying local adaptation. [ABSTRACT FROM AUTHOR]

Invasive species represent excellent opportunities to study the evolutionary potential of traits important to success in novel environments. Although some ecologically important traits have been identified in invasive species, little is typically known about the genetic mechanisms that underlie invasion success in non-model species. Here, we use a genome-wide association (GWAS) approach to identify the genetic basis of trait variation in the non-model, invasive, diffuse knapweed [Centaurea diffusa Lam. (Asteraceae)]. To assist with this analysis, we have assembled the first draft genome reference and fully annotated plastome assembly for this species, and one of the first from this large, weedy, genus, which is of major ecological and economic importance. We collected phenotype data from 372 individuals from four native and four invasive populations of C. diffusa grown in a common environment. Using these individuals, we produced reduced-representation genotype-by-sequencing (GBS) libraries and identified 7,058 SNPs. We identify two SNPs associated with leaf width in these populations, a trait which significantly varies between native and invasive populations. In this rosette forming species, increased leaf width is a major component of increased biomass, a common trait in invasive plants correlated with increased fitness. Finally, we use annotations from Arabidopsis thaliana to identify 98 candidate genes that are near the associated SNPs and highlight several good candidates for leaf width variation.

Ecological processes and intra-specific genetic diversity reciprocally affect each other. While the importance of uniting ecological variables and genetic variation to understand species’ plasticity, adaptation, and evolution is increasingly recognized, only few studies have attempted to address the intersection of population ecology and genetics using marine macrophyte as models. Representative empirical case studies on genetic diversity are reviewed that explore ecological and evolutionary processes in marine macrophytes. These include studies on environment-induced phenotypic plasticity and associated ecological adaptation; population genetic variation and structuring driven by ecological variation; and ecological consequences mediated by intraspecific and interspecific diversity. Knowledge gaps are also discussed that impede the connection of ecology and genetics in macrophytes and possible approaches to address these issues. Finally, an eco-evolutionary perspective is advocated, by incorporating structural-to-functional genomics and life cycle complexity, to increase the understanding of the adaptation and evolution of macrophytes in response to environmental heterogeneity.

Several papers deal with a conservation genetics gap in which plant conservation and restoration managers or practitioners do not soundly integrate population genetics information into conservation management. Authors concerned about this issue point out that practitioners perceive genetic research results to be impractical or unnecessary in the short term due to time and financial constraints. In addition, researchers often fail to translate research findings into comprehensive, jargon-free recommendations effectively. If possible, conservation-related or conservation-oriented articles should be easily written to bridge the research–implementation gap. Finally, based on a previously published prioritization framework for conservation genetics scenarios, we introduce four simple genetic categories by exemplifying each case. We hope that conservation practitioners could employ these suggested guidelines for the prioritization of population- and species-level management.

Genetic diversity is essential for populations to adapt to changing environments. Measures of genetic diversity are often based on selectively neutral markers, such as microsatellites. Genetic diversity to guide conservation management, however, is better reflected by adaptive markers, including genes of the major histocompatibility complex (MHC). Our aim was to assess MHC and neutral genetic diversity in two contrasting bottlenose dolphin (Tursiops aduncus) populations in Western Australia—one apparently viable population with high reproductive output (Shark Bay) and one with lower reproductive output that was forecast to decline (Bunbury). We assessed genetic variation in the two populations by sequencing the MHC class II DQB, which encompasses the functionally important peptide binding regions (PBR). Neutral genetic diversity was assessed by genotyping twenty‐three microsatellite loci. We confirmed that MHC is an adaptive marker in both populations. Overall, the Shark Bay population exhibited greater MHC diversity than the Bunbury population—for example, it displayed greater MHC nucleotide diversity. In contrast, the difference in microsatellite diversity between the two populations was comparatively low. Our findings are consistent with the hypothesis that viable populations typically display greater genetic diversity than less viable populations. The results also suggest that MHC variation is more closely associated with population viability than neutral genetic variation. Although the inferences from our findings are limited, because we only compared two populations, our results add to a growing number of studies that highlight the usefulness of MHC as a potentially suitable genetic marker for animal conservation. The Shark Bay population, which carries greater adaptive genetic diversity than the Bunbury population, is thus likely more robust to natural or human‐induced changes to the coastal ecosystem it inhabits. [ABSTRACT FROM AUTHOR]

Abstract Establishing corridors of connecting habitat has become a mainstay conservation strategy to maintain gene flow and facilitate climate‐driven range shifts. Yet, little attention has been given to ascertaining the extent to which corridors will benefit philopatric species, which might exhibit localized adaptation. Measures of genetic connectivity and adaptive genetic variation across species’ ranges can help fill this knowledge gap. Here, we characterized the spatial genetic structure of Cunningham's skink (Egernia cunninghami), a philopatric species distributed along Australia's Great Dividing Range, and assessed evidence of localized adaptation. Analysis of 4,274 SNPs from 94 individuals sampled at four localities spanning 500 km and 4° of latitude revealed strong genetic structuring at neutral loci (mean FST ± SD = 0.603 ± 0.237) among the localities. Putatively neutral SNPs and those under divergent selection yielded contrasting spatial patterns, with the latter identifying two genetically distinct clusters. Given low genetic connectivity of the four localities, we suggest that the natural movement rate of this species is insufficient to keep pace with spatial shifts to its climate envelope, irrespective of habitat availability. In addition, our finding of localized adaptation highlights the risk of outbreeding depression should the translocation of individuals be adopted as a conservation management strategy.

Overfishing and rapid environmental shifts pose severe challenges to the resilience and viability of marine fish populations. To develop and implement measures that enhance species’ adaptive potential to cope with those pressures while, at the same time, ensuring sustainable exploitation rates is part of the central goal of fisheries management. Here, we argue that a combination of biophysical modelling and population genomic assessments offer ideal management tools to define stocks, their physical connectivity and ultimately, their short-term adaptive potential. To date, biophysical modelling has often been confined to fisheries ecology whereas evolutionary hypotheses remain rarely considered. When identified, connectivity patterns are seldom explored to understand the evolution and distribution of adaptive genetic variation, a proxy for species’ evolutionary potential. Here, we describe a framework that expands on the conventional seascape genetics approach by using biophysical modelling and population genomics. The goals are to identify connectivity patterns and selective pressures, as well as putative adaptive variants directly responding to the selective pressures and, ultimately, link both to define testable hypotheses over species response to shifting ecological conditions and overexploitation. [ABSTRACT FROM AUTHOR]

Abstract: Detecting genetic variants under selection using FST outlier analysis (OA) and environmental association analyses (EAAs) are popular approaches that provide insight into the genetic basis of local adaptation. Despite the frequent use of OA and EAA approaches and their increasing attractiveness for detecting signatures of selection, their application to field‐based empirical data have not been synthesized. Here, we review 66 empirical studies that use Single Nucleotide Polymorphisms (SNPs) in OA and EAA. We report trends and biases across biological systems, sequencing methods, approaches, parameters, environmental variables and their influence on detecting signatures of selection. We found striking variability in both the use and reporting of environmental data and statistical parameters. For example, linkage disequilibrium among SNPs and numbers of unique SNP associations identified with EAA were rarely reported. The proportion of putatively adaptive SNPs detected varied widely among studies, and decreased with the number of SNPs analysed. We found that genomic sampling effort had a greater impact than biological sampling effort on the proportion of identified SNPs under selection. OA identified a higher proportion of outliers when more individuals were sampled, but this was not the case for EAA. To facilitate repeatability, interpretation and synthesis of studies detecting selection, we recommend that future studies consistently report geographical coordinates, environmental data, model parameters, linkage disequilibrium, and measures of genetic structure. Identifying standards for how OA and EAA studies are designed and reported will aid future transparency and comparability of SNP‐based selection studies and help to progress landscape and evolutionary genomics. [ABSTRACT FROM AUTHOR]

The mean phenotypic effects of a discovered variant help to predict major aspects of the evolution and inheritance of a phenotype. However, differences in the phenotypic variance associated to distinct genotypes are often overlooked despite being suggestive of processes that largely influence phenotypic evolution, such as interactions between the genotypes with the environment or the genetic background. We present empirical evidence for a mutation at the melanocortin-1-receptor gene, a major vertebrate coloration gene, affecting phenotypic variance in the barn owl, Tyto alba. The white MC1R allele, which associates with whiter plumage coloration, also associates with a pronounced phenotypic and additive genetic variance for distinct color traits. Contrarily, the rufous allele, associated with a rufous coloration, relates to a lower phenotypic and additive genetic variance, suggesting that this allele may be epistatic over other color loci. Variance differences between genotypes entailed differences in the strength of phenotypic and genetic associations between color traits, suggesting that differences in variance also alter the level of integration between traits. This study highlights that addressing variance differences of genotypes in wild populations provides interesting new insights into the evolutionary mechanisms and the genetic architecture underlying the phenotype. [ABSTRACT FROM AUTHOR]

Knowledge on adaptive genetic variation in response to environmental variation is the key to understanding the adaptive evolution potential of species. China's warm-temperate zone is an important climatic zone, but only a few landscape genomics studies have been conducted to understand the adaptive evolution of regional vegetation. In this study, natural populations of Achyranthes bidentata Blume were sampled in China's warm-temperate zone to infer its adaptive evolution using landscape genomics methods. Four SCoT primers were used to investigate the adaptive evolution of A. bidentata in response to environmental variation across the warm-temperate zone of China. A total of 126 individuals from fifteen natural populations were successfully scored, and 202 unambiguous fragments were obtained. Twenty-three outlier loci were identified, eighteen outlier loci were significantly associated with environmental variables. Redundancy analytical results suggested that four environmental variables related to temperature and precipitation remarkably influenced the distribution of loci. The results provide empirical evidence that molecular markers with bias toward candidate functional genes might be suitable for landscape genomics studies. Temperature and precipitation jointly drive the adaptive evolution of A. bidentata. The key driving environmental factors identified in this study are mostly related to the ecological habit of A. bidentata. The species personality, i.e., ecological habit, seems to play an important role in the adaptive differentiation on A. bidentata. [ABSTRACT FROM AUTHOR]

Identifying the genetic basis of phenotypic variation and its relationship with the environment is key to understanding how local adaptations evolve. Such patterns are especially interesting among populations distributed across habitat gradients, where genetic structure can be driven by isolation by distance ( IBD) and/or isolation by environment ( IBE). Here, we used variation in ~1,600 high-quality SNPs derived from paired-end sequencing of double-digest restriction site-associated DNA (dd RAD-Seq) to test hypotheses related to IBD and IBE in the Yucatan jay ( Cyanocorax yucatanicus), a tropical bird endemic to the Yucatán Peninsula. This peninsula is characterized by a precipitation and vegetation gradient-from dry to evergreen tropical forests-that is associated with morphological variation in this species. We found a moderate level of nucleotide diversity (π = .008) and little evidence for genetic differentiation among vegetation types. Analyses of neutral and putatively adaptive SNPs (identified by complementary genome-scan approaches) indicate that IBD is the most reliable explanation to account for frequency distribution of the former, while IBE has to be invoked to explain those of the later. These results suggest that selective factors acting along a vegetation gradient can promote local adaptation in the presence of gene flow in a vagile, nonmigratory and geographically restricted species. The putative candidate SNPs identified here are located within or linked to a variety of genes that represent ideal targets for future genomic surveys. [ABSTRACT FROM AUTHOR]

Functional trait variation within and across populations can strongly influence population, community, and ecosystem processes, but the relative contributions of genetic vs. environmental factors to this variation are often not clear, potentially complicating conservation and restoration efforts. For example, local adaptation, a particular type of genetic by environmental (G*E) interaction in which the fitness of a population in its own habitat is greater than in other habitats, is often invoked in management practices, even in the absence of supporting evidence. Despite increasing attention to the potential for G*E interactions, few studies have tested multiple populations and environments simultaneously, limiting our understanding of the spatial consistency in patterns of adaptive genetic variation. In addition, few studies explicitly differentiate adaptation in response to predation from other biological and environmental factors. We conducted a reciprocal transplant experiment of first-generation eastern oyster ( Crassostrea virginica) juveniles from six populations across three field sites spanning 1000 km in the southeastern Atlantic Bight in both the presence and absence of predation to test for G*E variation in this economically valuable and ecologically important species. We documented significant G*E variation in survival and growth, yet there was no evidence for local adaptation. Condition varied across oyster cohorts: Offspring of northern populations had better condition than offspring from the center of our region. Oyster populations in the southeastern Atlantic Bight differ in juvenile survival, growth, and condition, yet offspring from local broodstock do not have higher survival or growth than those from farther away. In the absence of population-specific performance information, oyster restoration and aquaculture may benefit from incorporating multiple populations into their practices. [ABSTRACT FROM AUTHOR]

Understanding the genecology of forest trees is critical for gene conservation, for predicting the effects of climate change and climate change adaptation, and for successful reforestation. Although common genecological patterns have emerged, species-specific details are also important. Which species are most vulnerable to climate change? Which are the most important adaptive traits and environmental drivers of natural selection? Even though species have been classified as adaptive specialists vs. adaptive generalists, large-scale studies comparing different species in the same experiment are rare. We studied the genecology of Norway spruce ( Picea abies) and silver fir ( Abies alba), two co-occurring but ecologically distinct European conifers in Central Europe. For each species, we collected seed from more than 90 populations across Switzerland, established a seedling common-garden test, and developed genecological models that associate population variation in seedling growth and phenology to climate, soil properties, and site water balance. Population differentiation and associations between seedling traits and environmental variables were much stronger for Norway spruce than for silver fir, and stronger for seedling height growth than for bud phenology. In Norway spruce, height growth and second flushing were strongly associated with temperature and elevation, with seedlings from the lowlands being taller and more prone to second flush than seedlings from the Alps. In silver fir, height growth was more weakly associated with temperature and elevation, but also associated with water availability. Soil characteristics explained little population variation in both species. We conclude that Norway spruce has become an adaptive specialist because trade-offs between rapid juvenile growth and frost avoidance have subjected it to strong diversifying natural selection based on temperature. In contrast, because silver fir has a more conservative growth habit, it has evolved to become an adaptive generalist. This study demonstrates that co-occurring tree species can develop very different adaptive strategies under identical environmental conditions, and suggests that Norway spruce might be more vulnerable to future maladaptation due to rapid climate change than silver fir. [ABSTRACT FROM AUTHOR]

Establishing corridors of connecting habitat has become a mainstay conservation strategy to maintain gene flow and facilitate climate-driven range shifts. Yet, little attention has been given to ascertaining the extent to which corridors will benefit philopatric species, which might exhibit localized adaptation. Measures of genetic connectivity and adaptive genetic variation across species' ranges can help fill this knowledge gap. Here, we characterized the spatial genetic structure of Cunningham's skink ( Egernia cunninghami), a philopatric species distributed along Australia's Great Dividing Range, and assessed evidence of localized adaptation. Analysis of 4,274 SNPs from 94 individuals sampled at four localities spanning 500 km and 4° of latitude revealed strong genetic structuring at neutral loci (mean FST ± SD = 0.603 ± 0.237) among the localities. Putatively neutral SNPs and those under divergent selection yielded contrasting spatial patterns, with the latter identifying two genetically distinct clusters. Given low genetic connectivity of the four localities, we suggest that the natural movement rate of this species is insufficient to keep pace with spatial shifts to its climate envelope, irrespective of habitat availability. In addition, our finding of localized adaptation highlights the risk of outbreeding depression should the translocation of individuals be adopted as a conservation management strategy. [ABSTRACT FROM AUTHOR]

Landscape genomics is an emerging research field that aims to identify the environmental factors that shape adaptive genetic variation and the gene variants that drive local adaptation. Its development has been facilitated by next-generation sequencing, which allows for screening thousands to millions of single nucleotide polymorphisms in many individuals and populations at reasonable costs. In parallel, data sets describing environmental factors have greatly improved and increasingly become publicly accessible. Accordingly, numerous analytical methods for environmental association studies have been developed. Environmental association analysis identifies genetic variants associated with particular environmental factors and has the potential to uncover adaptive patterns that are not discovered by traditional tests for the detection of outlier loci based on population genetic differentiation. We review methods for conducting environmental association analysis including categorical tests, logistic regressions, matrix correlations, general linear models and mixed effects models. We discuss the advantages and disadvantages of different approaches, provide a list of dedicated software packages and their specific properties, and stress the importance of incorporating neutral genetic structure in the analysis. We also touch on additional important aspects such as sampling design, environmental data preparation, pooled and reduced-representation sequencing, candidate-gene approaches, linearity of allele-environment associations and the combination of environmental association analyses with traditional outlier detection tests. We conclude by summarizing expected future directions in the field, such as the extension of statistical approaches, environmental association analysis for ecological gene annotation, and the need for replication and post hoc validation studies. [ABSTRACT FROM AUTHOR]

Understanding landscape processes driving patterns of population genetic differentiation and diversity has been a long-standing focus of ecology and evolutionary biology. Gene flow may be reduced by historical, ecological or geographic factors, resulting in patterns of isolation by distance ( IBD) or isolation by environment ( IBE). Although IBE has been found in many natural systems, most studies investigating patterns of IBD and IBE in nature have used anonymous neutral genetic markers, precluding inference of selection mechanisms or identification of genes potentially under selection. Using landscape genomics, the simultaneous study of genomic and ecological landscapes, we investigated the processes driving population genetic patterns of White-breasted Nuthatches ( Sitta carolinensis) in sky islands (montane forest habitat islands) of the Madrean Archipelago. Using more than 4000 single nucleotide polymorphisms and multiple tests to investigate the relationship between genetic differentiation and geographic or ecological distance, we identified IBE, and a lack of IBD, among sky island populations of S. carolinensis. Using three tests to identify selection, we found 79 loci putatively under selection; of these, seven matched CDS regions in the Zebra Finch. The loci under selection were highly associated with climate extremes (maximum temperature of warmest month and minimum precipitation of driest month). These results provide evidence for IBE - disentangled from IBD - in sky island vertebrates and identify potential adaptive genetic variation. [ABSTRACT FROM AUTHOR]

We used RAPD markers to study the population genetic structure and diversity of Saxifraga rosacea subsp. sponhemica, a rare Central European endemic rock plant with a highly disjunct distribution. Because of strong isolation current gene flow between populations is very low or absent. However, an isolation by distance pattern of genetic differentiation suggested historical gene flow during the last glaciation when suitable habitats for S. sponhemica were much more abundant. In most populations, considerable genetic variability has been preserved due to the longevity of S. sponhemica. Our results suggest that long-lived plant species can maintain historic genetic patterns despite small size and strong isolation of populations. Several RAPD loci were identified to be non-neutral and their frequencies correlated with climatic gradients, indicating natural selection. Adaptive genetic variation could be important for adaptation to environmental changes like ongoing climate change. The taxon does not appear to be genetically threatened in the short term, but populations are threatened by habitat destruction. The establishment of new populations in suitable habitats with seeds from the same region may be a suitable conservation measure avoiding potential maladaptation due to local adaptation. [ABSTRACT FROM AUTHOR]

Cork oak ( Quercus suber L.) is an evergreen tree species endemic to the western Mediterranean Basin with a major economical, social and ecological relevance, associated with cork extraction and exploitation. In the last years, cork oak stands have been facing a significant decline, which may be aggravated by the climate changes that are predicted to occur within cork oak distribution range during this century. Under this scenario, the assessment of adaptive genetic variation is essential to understand how cork oak may cope with these threats and to delineate strategies for the management of its genetic resources. In this study, six candidate genes possibly significant for environmental adaptation were analysed in cork oak populations from its entire distribution range. Signatures of natural selection were investigated using population genetic statistics and environmental association tests under alternative scenarios of population genetic structure. Signals of balancing selection were detected in the putative non-expressor of pathogenesis-related gene 1 ( NPR1), involved in plant defence response against pathogens, in auxin response factor 16 ( ARF16), a gene implicated in root development, in RAN3, also involved in developmental processes, and in glutamine synthetase nodule isozyme ( GS), involved in nitrogen fixation. Furthermore, for ARF16, a class I heat shock protein ( sHSP) and GS, associations were found between SNP allele and haplotype frequencies and several spatial and climatic variables, suggesting that these genes may have a role on cork oak local adaptation. In this study, the first steps were taken into gathering information on cork oak adaptation to environmental conditions. [ABSTRACT FROM AUTHOR]

Conserving genetic variation is critical for maintaining the evolutionary potential and viability of a species. Genetic studies seeking to delineate conservation units, however, typically focus on characterizing neutral genetic variation and may not identify populations harboring local adaptations. Here, variation at two major histocompatibility complex ( MHC) class II B genes was characterized in four populations of marbled murrelets Brachyramphus marmoratus, a threatened species in which little neutral genetic population structure has been detected. High diversity, as well as evidence of balancing selection, was detected in exon 2 of these genes. Genetic population structure based on MHC markers was uncorrelated to genetic structure estimated with neutral markers, suggesting that selection played a more important role in shaping population structure at these markers than genetic drift. A high proportion of alleles and inferred peptides were unique to a single population, with the Aleutian Islands and southeast Alaska having the highest richness of both. Murrelets sampled in Oregon had low MHC exon 2 allele and inferred peptide richness, and were significantly differentiated from individuals sampled in the Aleutian Islands based on the frequency of exon 2 alleles. In addition, murrelets sampled in Oregon were differentiated from murrelets in both the Aleutian Islands and southeast Alaska based on inferred peptide frequencies, suggesting that the Oregon population could be prioritized for conservation measures. More broadly, combining information from neutral and adaptive genetic markers can improve the delineation of conservation units in threatened species. [ABSTRACT FROM AUTHOR]

Unravelling the factors shaping the genetic structure of mobile marine species is challenging due to the high potential for gene flow. However, genetic inference can be greatly enhanced by increasing the genomic, geographical or environmental resolution of population genetic studies. Here, we investigated the population structure of turbot ( Scophthalmus maximus) by screening 17 random and gene-linked markers in 999 individuals at 290 geographical locations throughout the northeast Atlantic Ocean. A seascape genetics approach with the inclusion of high-resolution oceanographical data was used to quantify the association of genetic variation with spatial, temporal and environmental parameters. Neutral loci identified three subgroups: an Atlantic group, a Baltic Sea group and one on the Irish Shelf. The inclusion of loci putatively under selection suggested an additional break in the North Sea, subdividing southern from northern Atlantic individuals. Environmental and spatial seascape variables correlated marginally with neutral genetic variation, but explained significant proportions (respectively, 8.7% and 10.3%) of adaptive genetic variation. Environmental variables associated with outlier allele frequencies included salinity, temperature, bottom shear stress, dissolved oxygen concentration and depth of the pycnocline. Furthermore, levels of explained adaptive genetic variation differed markedly between basins (3% vs. 12% in the North and Baltic Sea, respectively). We suggest that stable environmental selection pressure contributes to relatively strong local adaptation in the Baltic Sea. Our seascape genetic approach using a large number of sampling locations and associated oceanographical data proved useful for the identification of population units as the basis of management decisions. [ABSTRACT FROM AUTHOR]

The Forest ecosystem genomics Research: supporTing Transatlantic Cooperation project (FoResTTraC, ) sponsored a workshop in August 2010 to evaluate the potential for using a landscape genomics approach for studying plant adaptation to the environment and the potential of local populations for coping with changing climate. This paper summarizes our discussions and articulates a vision of how we believe forest trees offer an unparalleled opportunity to address fundamental biological questions, as well as how the application of landscape genomic methods complement to traditional forest genetic approaches that provide critical information needed for natural resource management. In this paper, we will cover four topics. First, we begin by defining landscape genomics and briefly reviewing the unique situation for tree species in the application of this approach toward understanding plant adaptation to the environment. Second, we review traditional approaches in forest genetics for studying local adaptation and identifying loci underlying locally adapted phenotypes. Third, we present existing and emerging methods available for landscape genomic analyses. Finally, we briefly touch on how these approaches can aid in understanding practical topics such as management of tree populations facing climate change. [ABSTRACT FROM AUTHOR]

Understanding how landscape heterogeneity constrains gene flow and the spread of adaptive genetic variation is important for biological conservation given current global change. However, the integration of population genetics, landscape ecology and spatial statistics remains an interdisciplinary challenge at the levels of concepts and methods. We present a conceptual framework to relate the spatial distribution of genetic variation to the processes of gene flow and adaptation as regulated by spatial heterogeneity of the environment, while explicitly considering the spatial and temporal dynamics of landscapes, organisms and their genes. When selecting the appropriate analytical methods, it is necessary to consider the effects of multiple processes and the nature of population genetic data. Our framework relates key landscape genetics questions to four levels of analysis: (i) node-based methods, which model the spatial distribution of alleles at sampling locations (nodes) from local site characteristics; these methods are suitable for modeling adaptive genetic variation while accounting for the presence of spatial autocorrelation. (ii) Link-based methods, which model the probability of gene flow between two patches (link) and relate neutral molecular marker data to landscape heterogeneity; these methods are suitable for modeling neutral genetic variation but are subject to inferential problems, which may be alleviated by reducing links based on a network model of the population. (iii) Neighborhood-based methods, which model the connectivity of a focal patch with all other patches in its local neighborhood; these methods provide a link to metapopulation theory and landscape connectivity modeling and may allow the integration of node- and link-based information, but applications in landscape genetics are still limited. (iv) Boundary-based methods, which delineate genetically homogeneous populations and infer the location of genetic boundaries; these methods are suitable for testing for barrier effects of landscape features in a hypothesis-testing framework. We conclude that the power to detect the effect of landscape heterogeneity on the spatial distribution of genetic variation can be increased by explicit consideration of underlying assumptions and choice of an appropriate analytical approach depending on the research question. [ABSTRACT FROM AUTHOR]

It is generally accepted that most plant populations are locally adapted. Yet, understanding how environmental forces give rise to adaptive genetic variation is a challenge in conservation genetics and crucial to the preservation of species under rapidly changing climatic conditions. Environmental variation, phylogeographic history, and population demographic processes all contribute to spatially structured genetic variation, however few current models attempt to separate these confounding effects. To illustrate the benefits of using a spatially-explicit model for identifying potentially adaptive loci, we compared outlier locus detection methods with a recently-developed landscape genetic approach. We analyzed 157 loci from samples of the alpine herb Gentiana nivalis collected across the European Alps. Principle coordinates of neighbor matrices (PCNM), eigenvectors that quantify multi-scale spatial variation present in a data set, were incorporated into a landscape genetic approach relating AFLP frequencies with 23 environmental variables. Four major findings emerged. 1) Fifteen loci were significantly correlated with at least one predictor variable (R > 0.5). 2) Models including PCNM variables identified eight more potentially adaptive loci than models run without spatial variables. 3) When compared to outlier detection methods, the landscape genetic approach detected four of the same loci plus 11 additional loci. 4) Temperature, precipitation, and solar radiation were the three major environmental factors driving potentially adaptive genetic variation in G. nivalis. Techniques presented in this paper offer an efficient method for identifying potentially adaptive genetic variation and associated environmental forces of selection, providing an important step forward for the conservation of non-model species under global change. [ABSTRACT FROM AUTHOR]

The article presents a study on the adaptive genetic structuring at local and microgeographical scales where the neutral genetic markers have shown limited levels of population structure. The study was conducted by researchers where they analyzed 92 gene-associated single-nucleotide polymorphism (SNP) markers in Atlantic cod Gadus morhua which are taken from different sampling sites within the North Sea and adjacent areas. They also included long- and short-term temporally replicated samples from a subset of populations. The result of the study reveals the separation of populations under evolutionary and ecological paradigms and it shows the advantage of the spatio-temporal approach in making inferences about the dynamics of adaptive genetic variation in natural populations.

The study of the genetic variation of early height growth traits in seedlings helps to predict the possible outcomes of tree populations in the face of climate change. Second-year height growth of 10 geographically marginal populations of Patagonian cypress ( Austrocedrus chilensis (D. Don) Pic. Ser. et Bizzarri) (Cupressaceae) was characterized under greenhouse conditions. Variation among and within an average of 15 open-pollinated families (comprising 21 seedlings per family) for each population was analysed for six size and timing traits obtained from fitted Boltzmann growth curves. The among-family and among-population variances were 4.03% and 2.74% of the total phenotypic variation, while the residual variance was 84.57% on average. Genetic differentiation among populations was low, except for the maximum growth rate ( Q = 0.35) and for growth initiation ( Q = 1). For most traits, genetic variation and heritability were variable across populations, except for growth initiation, which showed in general null intra-population levels of genetic variance. Although no direct associations were found between the additive genetic variation and latitude or altitude, the north range of the distribution was more variable for the pool of the analysed traits. Although most extreme-marginal populations of A. chilensis would be very limited in their ability to evolve if climate in north-west Patagonia turns drier and warmer, their long-term persistence could largely rely on a phenotypic diversification strategy. [ABSTRACT FROM AUTHOR]

Understanding the genetic basis of adaptation in response to environmental variation is fundamental as adaptation plays a key role in the extension of ecological niches to marginal habitats and in ecological speciation. Based on the assumption that some genomic markers are correlated to environmental variables, we aimed to detect loci of ecological relevance in the alpine plant Arabis alpina L. sampled in two regions, the French (99 locations) and the Swiss (109 locations) Alps. We used an unusually large genome scan [825 amplified fragment length polymorphism loci (AFLPs)] and four environmental variables related to temperature, precipitation and topography. We detected linkage disequilibrium among only 3.5% of the considered AFLP loci. A population structure analysis identified no admixture in the study regions, and the French and Swiss Alps were differentiated and therefore could be considered as two independent regions. We applied generalized estimating equations (GEE) to detect ecologically relevant loci separately in the French and Swiss Alps. We identified 78 loci of ecological relevance (9%), which were mainly related to mean annual minimum temperature. Only four of these loci were common across the French and Swiss Alps. Finally, we discuss that the genomic characterization of these ecologically relevant loci, as identified in this study, opens up new perspectives for studying functional ecology in A. alpina, its relatives and other alpine plant species. [ABSTRACT FROM AUTHOR]

Landscape genetics is an emerging interdisciplinary field that combines methods and concepts from population genetics, landscape ecology, and spatial statistics. The interest in landscape genetics is steadily increasing, and the field is evolving rapidly. We here outline four major challenges for future landscape genetic research that were identified during an international landscape genetics workshop. These challenges include (1) the identification of appropriate spatial and temporal scales; (2) current analytical limitations; (3) the expansion of the current focus in landscape genetics; and (4) interdisciplinary communication and education. Addressing these research challenges will greatly improve landscape genetic applications, and positively contribute to the future growth of this promising field. [ABSTRACT FROM AUTHOR]

Knowledge of geographic and temporal scales of adaptive genetic variation is crucial to species conservation, yet understanding of these phenomena, particularly in marine systems, is scant. Until recently, the belief has been that because most marine species have highly dispersive or mobile life stages, local adaptation could occur only on broad geographic scales. This view is supported by comparatively low levels of genetic variation among populations as detected by neutral markers. Similarly, the time scale of adaptive divergence has also been assumed to be very long, requiring thousands of generations. Recent studies of a variety of species have challenged these beliefs. First, there is strong evidence of geographically structured local adaptation in physiological and morphological traits. Second, the proportion of quantitative trait variation at the among-population level ( QST) is much higher than it is for neutral markers ( FST) and these two metrics of genetic variation are poorly correlated. Third, evidence that selection is a potent evolutionary force capable of sustaining adaptive divergence on contemporary time scales is summarized. The differing spatial and temporal scales of adaptive v. neutral genetic divergence call for a new paradigm in thinking about the relationship between phenogeography (the geography of phenotypic variation) and phylogeography (the geography of lineages) in marine species. The idea that contemporary selective processes can cause fine-scale spatial and temporal divergence underscores the need for a new emphasis on Darwinian fishery science. [ABSTRACT FROM AUTHOR]

Genetic diversity is important for the maintenance of the viability and the evolutionary or adaptive potential of populations and species. However, there are two principal types of genetic diversity: adaptive and neutral—a fact widely neglected by non-specialists. We introduce these two types of genetic diversity and critically point to their potential uses and misuses in population or landscape genetic studies. First, most molecular-genetic laboratory techniques analyse neutral genetic variation. This means that the gene variants detected do not have any direct effect on fitness. This type of genetic variation is thus selectively neutral and tells us nothing about the adaptive or evolutionary potential of a population or a species. Nevertheless, neutral genetic markers have great potential for investigating processes such as gene flow, migration or dispersal. Hence, they allow us to empirically test the functional relevance of spatial indices such as connectivity used in landscape ecology. Second, adaptive genetic variation, i.e. genetic variation under natural selection, is analysed in quantitative genetic experiments under controlled and uniform environmental conditions. Unfortunately, the genetic variation (i.e. heritability) and population differentiation at quantitative, adaptive traits is not directly linked with neutral genetic diversity or differentiation. Thus, neutral genetic data cannot serve as a surrogate of adaptive genetic data. In summary, neutral genetic diversity is well suited for the study of processes within landscapes such as gene flow, while the evolutionary or adaptive potential of populations or species has to be assessed in quantitative genetic experiments. Landscape ecologists have to mind these differences between neutral and adaptive genetic variation when interpreting the results of landscape genetic studies. [ABSTRACT FROM AUTHOR]