scholarly journals Evolutionary potential varies across populations and traits in the neotropical oak Quercus oleoides

2018 ◽  
Vol 39 (3) ◽  
pp. 427-439 ◽  
Author(s):  
José A Ramírez-Valiente ◽  
Julie R Etterson ◽  
Nicholas J Deacon ◽  
Jeannine Cavender-Bares
Keyword(s):  
Climate Change ◽  
Genetic Variation ◽  
Genetic Structure ◽  
Additive Genetic Variance ◽  
Evolutionary Potential ◽  
Heritable Variation ◽  
Narrow Sense Heritability ◽  
Additive Genetic Variation ◽  
Quantitative Genetic ◽  
Quercus Oleoides

Abstract Heritable variation in polygenic (quantitative) traits is critical for adaptive evolution and is especially important in this era of rapid climate change. In this study, we examined the levels of quantitative genetic variation of populations of the tropical tree Quercus oleoides Cham. and Schlect. for a suite of traits related to resource use and drought resistance. We tested whether quantitative genetic variation differed across traits, populations and watering treatments. We also tested potential evolutionary factors that might have shaped such a pattern: selection by climate and genetic drift. We measured 15 functional traits on 1322 1-year-old seedlings of 84 maternal half-sib families originating from five populations growing under two watering treatments in a greenhouse. We estimated the additive genetic variance, coefficient of additive genetic variation and narrow-sense heritability for each combination of traits, populations and treatments. In addition, we genotyped a total of 119 individuals (with at least 20 individuals per population) using nuclear microsatellites to estimate genetic diversity and population genetic structure. Our results showed that gas exchange traits and growth exhibited strikingly high quantitative genetic variation compared with traits related to leaf morphology, anatomy and photochemistry. Quantitative genetic variation differed between populations even at geographical scales as small as a few kilometers. Climate was associated with quantitative genetic variation, but only weakly. Genetic structure and diversity in neutral markers did not relate to coefficient of additive genetic variation. Our study demonstrates that quantitative genetic variation is not homogeneous across traits and populations of Q. oleoides. More importantly, our findings suggest that predictions about potential responses of species to climate change need to consider population-specific evolutionary characteristics.

scholarly journals Genetic Variation Explains Changes in Susceptibility in a Naïve Host Against an Invasive Forest Pathogen: The Case of Alder and the Phytophthora alni Complex

2020 ◽  
Vol 110 (2) ◽  
pp. 517-525 ◽  
Author(s):  
Miguel A. Redondo ◽  
Jan Stenlid ◽  
Jonàs Oliva
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Transmission Rate ◽  
Alternative Hypothesis ◽  
Simulated Data ◽  
Alnus Glutinosa ◽  
Heritable Variation ◽  
Narrow Sense Heritability ◽  
Black Alder

Predicting whether naïve tree populations have the potential to adapt to exotic pathogens is necessary owing to the increasing rate of invasions. Adaptation may occur as a result of natural selection when heritable variation in terms of susceptibility exists in the naïve population. We searched for signs of selection on black alder (Alnus glutinosa) stands growing on riverbanks invaded by two pathogens differing in aggressiveness, namely, Phytophthora uniformis (PU) and Phytophthora × alni (PA). We compared the survival and heritability measures from 72 families originating from six invaded and uninvaded (naïve) sites by performing in vitro inoculations. The results from the inoculations were used to assess the relative contribution of host genetic variation on natural selection. We found putative signs of natural selection on alder exerted by PU but not by PA. For PU, we found a higher survival in families originating from invaded sites compared with uninvaded sites. The narrow sense heritability of susceptibility to PU of uninvaded populations was significantly higher than to PA. Simulated data supported the role of heritable genetic variation on natural selection and discarded a high aggressiveness of PA decreasing the transmission rate as an alternative hypothesis for a slow natural selection. Our findings expand on previous attempts of using heritability as a predictor for the likelihood of natural adaptation of naïve tree populations to invasive pathogens. Measures of genetic variation can be useful for risk assessment purposes or when managing Phytophthora invasions.

scholarly journals Assessment of local genetic structure and connectivity of the common eelgrass Zostera marina for seagrass restoration in northern Europe

2021 ◽  
Vol 664 ◽  
pp. 103-116
Author(s):  
L Martínez-García ◽  
B Hansson ◽  
J Hollander
Keyword(s):  
Climate Change ◽  
Genetic Variation ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Baltic Sea ◽  
Zostera Marina ◽  
Anthropogenic Impacts ◽  
Ecosystem Functions ◽  
Long Distance ◽  
Seagrass Meadows

Seagrass meadows are one of the most important habitats in coastal regions since they constitute a multifunctional ecosystem providing high productivity and biodiversity. They play a key role in carbon sequestration capacity, mitigation against coastal erosion and as nursery grounds for many marine fish and invertebrates. However, despite these ecosystem functions and services, seagrass meadows are a threatened ecosystem worldwide. In the Baltic Sea, seagrass meadows have declined rapidly, mainly because of eutrophication, anthropogenic activities and climate change. This decline has the potential to erode the genetic variation and genetic structure of the species. In this study, we assessed how genetic variation and genetic differentiation vary among Zostera marina meadows and with a number of environmental characteristics in the county of Scania in southern Sweden. A total of 205 individuals sampled at 12 locations were analysed with 10 polymorphic microsatellite loci. Results showed that in spite of anthropogenic impacts and climate change pressures, locations of Z. marina possessed high genetic variation and weak genetic differentiation, with 3 major genetic clusters. Long-distance dispersal and/or stepping-stone dispersal was found among locations, with higher migration rates within the west coast. Organic matter, salinity and maximum depth appeared to be factors most strongly associated with the genetic structure and morphological variation of Z. marina. These findings contribute significantly in the identification of potential donor sites and the viability of impacted areas to recover from natural recruitment, for the development of effective transplantation measures of Z. marina in the southern Baltic Sea and temperate regions elsewhere.

scholarly journals Genotyping-by-sequencing reveals the effects of riverscape, climate and interspecific introgression on the genetic diversity and local adaptation of the endangered Mexican golden trout (Oncorhynchus chrysogaster)

2018 ◽  
Author(s):  
Marco A. Escalante ◽  
Charles Perrier ◽  
Francisco J. García-De León ◽  
Arturo Ruiz-Luna ◽  
Enrique Ortega-Abboud ◽  
...  
Keyword(s):  
Climate Change ◽  
Genetic Diversity ◽  
Genetic Variation ◽  
Local Adaptation ◽  
Population Genomics ◽  
Landscape Heterogeneity ◽  
Genotyping By Sequencing ◽  
Anthropogenic Factors ◽  
Nucleotide Polymorphisms ◽  
Evolutionary Potential

AbstractHow environmental and anthropogenic factors influence genetic variation and local adaptation is a central issue in evolutionary biology. The Mexican golden trout (Oncorhynchus chrysogaster), one of the southernmost native salmonid species in the world, is susceptible to climate change, habitat perturbations and the competition and hybridization with exotic rainbow trout (O. mykiss). The present study aimed for the first time to use genotyping-by-sequencing to explore the effect of genetic hybridization with O. mykiss and of riverscape and climatic variables on the genetic variation among O. chrysogaster populations. Genotyping-by-sequencing (GBS) was applied to generate 9767 single nucleotide polymorphisms (SNPs), genotyping 272 O. chrysogaster and O. mykiss. Population genomics analyses were combined with landscape ecology approaches into a riverine context (riverscape genetics). The clustering analyses detected seven different genetic groups (six for O. chrysogater and one for aquaculture O. mykiss) and a small amount of admixture between aquaculture and native trout with only two native genetic clusters showing exotic introgression. Latitude and precipitation of the driest month had a significant negative effect on genetic diversity and evidence of isolation by river resistance was detected, suggesting that the landscape heterogeneity was preventing trout dispersal, both for native and exotic individuals. Moreover, several outlier SNPs were identified as potentially implicated in local adaptation to local hydroclimatic variables. Overall, this study suggests that O. chrysogater may require conservation planning given i) exotic introgression from O. mykiss locally threatening O. chrysogater genetic integrity, and ii) putative local adaptation but low genetic diversity and hence probably reduced evolutionary potential especially in a climate change context.

scholarly journals Quantifying multivariate genotype-by-environment interactions, evolutionary potential and its context-dependence in natural populations of the water flea, Daphnia magna

2020 ◽  
Author(s):  
Franziska S. Brunner ◽  
Alan Reynolds ◽  
Ian W. Wilson ◽  
Stephen Price ◽  
Steve Paterson ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Daphnia Magna ◽  
Natural Populations ◽  
Thermal Adaptation ◽  
Plastic Response ◽  
Evolutionary Potential ◽  
Genotype By Environment Interactions ◽  
Additive Genetic Variation ◽  
Genotype By Environment ◽  
Plastic Responses

ABSTRACTGenotype-by-environment interactions (G x E) underpin the evolution of plastic responses in natural populations. Theory assumes that G x E interactions exist but empirical evidence from natural populations is equivocal and difficult to interpret because G x E interactions are normally univariate plastic responses to a single environmental gradient. We compared multivariate plastic responses of 43 Daphnia magna clones from the same population in a factorial experiment that crossed temperature and food environments. Multivariate plastic responses explained more than 30% of the total phenotypic variation in each environment. G x E interactions were detected in most environment combinations irrespective of the methodology used. However, the nature of G x E interactions was context-dependent and led to environment-specific differences in additive genetic variation (G-matrices). Clones that deviated from the population average plastic response were not the same in each environmental context and there was no difference in whether clones varied in the nature (phenotypic integration) or magnitude of their plastic response in different environments. Plastic responses to food were aligned with additive genetic variation (gmax) at both temperatures, whereas plastic responses to temperature were not aligned with additive genetic variation (gmax) in either food environment. These results suggest that fundamental differences may exist in the potential for our population to evolve novel responses to food versus temperature changes, and challenges past interpretations of thermal adaptation based on univariate studies.

Genetic variation for resistance to clinical and subclinical diseases exists in growing pigs

2001 ◽  
Vol 73 (3) ◽  
pp. 375-387 ◽  
Author(s):  
M. Henryon ◽  
P. Berg ◽  
J. Jensen ◽  
S. Andersen
Keyword(s):  
Genetic Variation ◽  
Respiratory Diseases ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Frailty Model ◽  
Growing Pigs ◽  
Disease Category ◽  
Breeding Values ◽  
Additive Genetic Variation ◽  
Subclinical Disease

AbstractThe objective of this study was to test that genetic variation for resistance to clinical and subclinical diseases exists in growing pigs. A total of 13 551 male growing pigs were assessed for resistance to five categories of clinical and subclinical disease: (i) any clinical or subclinical disease, (ii) lameness, (iii) respiratory diseases, (iv) diarrhoea, and (v) other diseases (i.e. any clinical or subclinical disease with the exception of (ii), (iii), and (iv)). Additive genetic variation for resistance to each disease category was estimated by fitting a Weibull, sire-dam frailty model to time until the pigs were first diagnosed with a disease from that category. Genetic correlations among the resistances to each disease category were approximated as product-moment correlations among predicted breeding values of the sires. Additive genetic variation was detected for resistance to (i) any clinical or subclinical disease (additive genetic variance for log-frailty (± s.e.) = 0·18 ± 0·05, heritability on the logarithmic-time scale = 0·10), (ii) lameness (0·29 ± 0·11, 0·16), (iii) respiratory diseases (0·24 ± 0·16, 0·12), (iv) diarrhoea (0·30 ± 0·27, 0·16), and (v) the other diseases (0·34 ± 0·15, 0·19) and there were generally positive and low-to-moderate correlations among the predicted breeding values (-0·03 to + 0·65). These results demonstrate that additive genetic variation for resistance to clinical and subclinical diseases does exist in growing pigs, and suggests that selective breeding for resistance could be successful.

scholarly journals Plastic responses to novel environments are biased towards phenotype dimensions with high additive genetic variation

2019 ◽  
Vol 116 (27) ◽  
pp. 13452-13461 ◽  
Author(s):  
Daniel W. A. Noble ◽  
Reinder Radersma ◽  
Tobias Uller
Keyword(s):  
Genetic Variation ◽  
Meta Analysis ◽  
Additive Genetic Variance ◽  
Genetic Mutation ◽  
Developmental Systems ◽  
Additive Genetic Variation ◽  
Genetic Constraint ◽  
Novel Environments ◽  
Plastic Responses

Environmentally induced phenotypes have been proposed to initiate and bias adaptive evolutionary change toward particular directions. The potential for this to happen depends in part on how well plastic responses are aligned with the additive genetic variance and covariance in traits. Using meta-analysis, we demonstrate that plastic responses to novel environments tend to occur along phenotype dimensions that harbor substantial amounts of additive genetic variation. This suggests that selection for or against environmentally induced phenotypes typically will be effective. One interpretation of the alignment between the direction of plasticity and the main axis of additive genetic variation is that developmental systems tend to respond to environmental novelty as they do to genetic mutation. This makes it challenging to distinguish if the direction of evolution is biased by plasticity or genetic “constraint.” Our results therefore highlight a need for new theoretical and empirical approaches to address the role of plasticity in evolution.

scholarly journals The evolutionary potential of diet-dependent effects on lifespan and fecundity in a multi-parental population of Drosophila melanogaster

2018 ◽  
Author(s):  
Enoch Ng’oma ◽  
Wilton Fidelis ◽  
Kevin M. Middleton ◽  
Elizabeth G. King
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Evolutionary Potential ◽  
Fitness Components ◽  
Nutrient Imbalance ◽  
Quantitative Genetic ◽  
Nutritional Conditions ◽  
Quantitative Genetic Parameters

AbstractThe nutritional conditions experienced by a population play a major role in shaping trait evolution in many taxa. Constraints exerted by nutrient limitation or nutrient imbalance can influence the maximal value that fitness components such as reproduction and lifespan attains, and organisms may shift how resources are allocated to different structures and functions in response to changes in nutrition. Whether the phenotypic changes associated with changes in nutrition represent an adaptive response is largely unknown. Further, it is unclear whether the response of fitness components to diet even has the potential to evolve in most systems. In this study, we use an admixed multiparental population of Drosophila melanogaster reared in three different diet conditions to estimate quantitative genetic parameters for lifespan and fecundity. We find significant genetic variation for both traits in our population and show that lifespan has moderate to high heritabilities within diets. Genetic correlations for lifespan between diets were significantly less than one, demonstrating a strong genotype by diet interaction. These findings demonstrate substantial standing genetic variation in our population that is comparable to natural populations and highlights the potential for adaptation to changing nutritional environments.

scholarly journals Genetic variation in parental effects contribute to the evolutionary potential of prey responses to predation risk

2019 ◽  
Author(s):  
Natasha Tigreros ◽  
Anurag A. Agrawal ◽  
Jennifer S. Thaler
Keyword(s):  
Genetic Variation ◽  
Predation Risk ◽  
Evolutionary Dynamics ◽  
Leaf Beetle ◽  
Parental Effects ◽  
Evolutionary Potential ◽  
Additive Genetic Variation ◽  
Heritable Trait ◽  
Antipredator Responses ◽  
Potential Impact

ABSTRACTDespite the ubiquity of parental effects and their potential impact on evolutionary dynamics, their contribution to the evolution of ecologically relevant adaptations remains poorly understood. Using quantitative genetics, here we demonstrate that parental effects contribute substantially to the evolutionary potential of larval antipredator responses in a leaf beetle (Leptinotarsa decemlineata). Previous research showed that larger L. decemlineata larvae elicit stronger antipredator responses, and mothers perceiving predators improved offspring responses by increasing intraclutch cannibalism –an extreme form of offspring provisioning. We now report substantial additive genetic variation underlying maternal ability to induce intraclutch cannibalism, indicating the potential of this adaptive maternal effect to evolve by natural selection. We also show that paternal size, a heritable trait, impacted larval responses to predation risk, but that larval responses themselves had little additive genetic variation. Together, these results demonstrate how larval responses to predation risk can evolve via two types of parental effects, both of which provide indirect sources of genetic variation for offspring traits.

scholarly journals Heritable variation in bleaching responses and its functional genomic basis in reef-building corals (Orbicella faveolata)

2017 ◽  
Author(s):  
Katherine Dziedzic ◽  
Holland Elder ◽  
Hannah F Tavalire ◽  
Eli Meyer
Keyword(s):  
Genetic Variation ◽  
Thermal Stress ◽  
Stress Responses ◽  
Genetic Relatedness ◽  
Natural Populations ◽  
Adaptive Responses ◽  
Heritable Variation ◽  
Narrow Sense Heritability ◽  
Functional Basis ◽  
Orbicella Faveolata

Reef-building corals are highly sensitive to rising ocean temperatures, and substantial adaptation will be required for corals and the ecosystems they support to persist in changing ocean conditions. Genetic variation that might support adaptive responses has been measured in larval stages of some corals, but these estimates remain unavailable for adult corals and the functional basis of this variation remains unclear. In this study, we focused on the potential for adaptation in Orbicella faveolata, a dominant reef-builder in the Caribbean. We conducted thermal stress experiments using corals collected from natural populations in Bocas del Toro, Panama, and used multilocus SNP genotypes to estimate genetic relatedness among samples. This allowed us to estimate narrow-sense heritability of variation in bleaching responses, revealing that variation in these responses was highly heritable (h2=0.58). This suggests substantial potential for adaptive responses to warming by natural populations of O. faveolata in this region. We further investigated the functional basis for this variation using genomic and transcriptomic approaches. We used a publicly available genetic linkage map and genome assembly to map markers associated with bleaching responses, identifying twelve markers associated with variation in bleaching responses. We also profiled gene expression in corals with contrasting bleaching phenotypes, uncovering substantial differences in transcriptional stress responses between heat-tolerant and heat-susceptible corals. Together, our findings contribute to the growing body of evidence that natural populations of corals possess genetic variation in thermal stress responses that may potentially support adaptive responses to rising ocean temperatures.

scholarly journals Quantitative Genetic Variation in Bark Stripping of Pinus radiata

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1356
Author(s):  
Judith S. Nantongo ◽  
Brad M. Potts ◽  
Hugh Fitzgerald ◽  
Jessica Newman ◽  
Stephen Elms ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Pinus Radiata ◽  
Plant Traits ◽  
Tree Age ◽  
Physical Factors ◽  
Environment Interaction ◽  
Bark Stripping ◽  
Narrow Sense Heritability ◽  
Additive Genetic Variation ◽  
Chemical Traits

Bark stripping by mammals is a major problem for conifer forestry worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials. As a sustainable management option, we explored the extent to which natural variation in the susceptibility of P. radiata is under genetic control and is thus amenable to genetic improvement. Bark stripping was assessed at ages four and five years in two sister trials comprising 101 and 138 open-pollinated half-sib families. A third younger trial comprising 74 full-sib control-pollinated families was assessed at two and three years after planting. Significant additive genetic variation in bark stripping was demonstrated in all trials, with narrow-sense heritability estimates between 0.06 and 0.14. Within sites, the amount of additive genetic variation detected increased with the level of bark stripping. When strongly expressed across the two sister trials, the genetic signal was stable (i.e., there was little genotype × environment interaction). No significant non-additive effect (specific combining ability effect) on bark stripping was detected in the full-sib family trial, where it was estimated that up to 22.1% reduction in bark stripping might be achieved by selecting 20% of the less susceptible families. Physical traits that were genetically correlated, and likely influenced the amount of bark removed from the trees by the marsupials, appeared to depend upon tree age. In the older trials, these traits included bark features (presence of rough bark, rough bark height, and bark thickness), whereas in the younger trial where rough bark was not developed, it was the presence of obstructive branches or needles on the stem. In the younger trial, a positive genetic correlation between prior height and bark stripping was detected, suggesting that initially faster growing trees exhibit more bark stripping than slower growing trees but later develop rough bark faster and became less susceptible. While the presence of unexplained genetic variation after accounting for these physical factors suggests that other explanatory plant traits may be involved, such as chemical traits, overall the results indicate that selection for reduced susceptibility is possible, with potential genetic gains for deployment and breeding.

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