Project description:The interplay between phenotypic plasticity and adaptive evolution has long been an important topic of evolutionary biology. This process is critical to our understanding of a species evolutionary potential in light of rapid climate changes. Despite recent theoretical work, empirical studies of natural populations, especially in marine invertebrates, are scarce. In this study, we investigated the relationship between adaptive divergence and plasticity by integrating genetic and phenotypic variation in Pacific oysters from its natural range in China. Genome resequencing of 371 oysters revealed unexpected fine-scale genetic structure that is largely consistent with phenotypic divergence in growth, physiology, thermal tolerance and gene expression across environmental gradient. These findings suggest that selection and local adaptation are pervasive and together with limited gene flow shape adaptive divergence. Plasticity in gene expression is positively correlated with evolved divergence, indicating that plasticity is adaptive and likely favored by selection in organisms facing dynamic environments such as oysters. Divergence in heat response and tolerance implies that the evolutionary potential to a warming climate differs among oyster populations. We suggest that trade-offs in energy allocation are important to adaptive divergence with acetylation playing a role in energy depression under thermal stress.
Project description:D. grimshawi microarray used to text for gene expression differences between two populations subjected to control or low-intensity heat for one week during maturation Anthropogenic influences on global processes and climatic conditions are increasingly affecting ecosystems throughout the world. Hawaii Island’s native ecosystems are well-studied and local long-term climatic trends well-documented, making these ecosystems ideal for evaluating how native taxa may respond to a warming environment. This study documents adaptive divergence of populations of a Hawaiian picture wing Drosophila, D. sproati, that are separated by only 7km and 365m in elevation. Representative laboratory populations show divergent behavioral and physiological responses to an experimental low-intensity increase in ambient temperature during maturation. The significant interaction of source population by temperature treatment for behavioral and physiological measurements indicates differential adaptation to temperature for the two populations. Significant differences in gene expression among males were mostly explained by the source population, with eleven genes in males also showing a significant interaction of source population by temperature treatment. The combined behavior, physiology, and gene expression differences between populations illustrates the potential for local adaptation to occur over a fine spatial scale and exemplifies nuanced response to climate change.
2018-11-27 | GSE122959 | GEO
Project description:Local adaptation despite gene flow in copepod populations across salinity and temperature gradients in the Baltic and North Seas
| PRJNA923656 | ENA
Project description:RNA-seq of Atlantic silverside larvae
Project description:We used custom Nimblegen microarrays representing whole-larval transcriptomes for two species (Erynnis propertius [this submission] and Papilio zelicaon [submitted seperately]) to assess gene expression differences affecting tolerance to climatic regimes. Many individuals were sourced from populations from the northern periphery and center of the species' (shared) range; these were each divided into groups treated under peripheral and central climate regimes, resulting in 4 experimental groups for each species (Peripheral Source, Peripheral treatment; Peripheral Source, Central Treatment; Central Source, Peripheral Treatment; Central Source, Central Treatment). Using technical microarray replicates allowed us to use ANOVA to identify genes whose expression may underlie local adaptation to climate (i.e., those showing an interaction term between source and population). Abstract: Population differences may determine geographic range shifts and adaptive evolution under climate change. Local adaptation in peripheral populations could preclude or slow range expansions, and populations with different genetic make-up could have distinct trajectories that produce complex spatial patterns of population change. To investigate the genetic extent of local responses to climate change, we exposed poleward-periphery and central populations of two Lepidoptera to reciprocal, common-garden climatic conditions and compared whole-transcriptome expression. We found significant expression differences between populations in both species. In addition, several hundred genes including genes involved in energy metabolism and oxidative stress responded in a localized fashion in the species that exhibits greater population structure and local adaptation. Expression levels of these genes are most divergent in the same environment in which we previously detected phenotypic divergence in metabolism. By contrast, we found no localized genes in the species with higher gene flow, reflecting the lack of previously observed local adaptation. These results suggest that population differences do not generalize easily, even for related species living in the same climate, but some taxa deserve population-level consideration when predicting the effects of climate change.
Project description:We used custom Nimblegen microarrays representing whole-larval transcriptomes for two species (Papilio zelicaon [this submission] and Erynnis propertius [submitted seperately]) to assess gene expression differences affecting tolerance to climatic regimes. Many individuals were sourced from populations from the northern periphery and center of the species' (shared) range; these were each divided into groups treated under peripheral and central climate regimes, resulting in 4 experimental groups for each species (Peripheral Source, Peripheral treatment; Peripheral Source, Central Treatment; Central Source, Peripheral Treatment; Central Source, Central Treatment). Using technical microarray replicates allowed us to use ANOVA to identify genes whose expression may underlie local adaptation to climate (i.e., those showing an interaction term between source and population). Abstract: Population differences may determine geographic range shifts and adaptive evolution under climate change. Local adaptation in peripheral populations could preclude or slow range expansions, and populations with different genetic make-up could have distinct trajectories that produce complex spatial patterns of population change. To investigate the genetic extent of local responses to climate change, we exposed poleward-periphery and central populations of two Lepidoptera to reciprocal, common-garden climatic conditions and compared whole-transcriptome expression. We found significant expression differences between populations in both species. In addition, several hundred genes including genes involved in energy metabolism and oxidative stress responded in a localized fashion in the species that exhibits greater population structure and local adaptation. Expression levels of these genes are most divergent in the same environment in which we previously detected phenotypic divergence in metabolism. By contrast, we found no localized genes in the species with higher gene flow, reflecting the lack of previously observed local adaptation. These results suggest that population differences do not generalize easily, even for related species living in the same climate, but some taxa deserve population-level consideration when predicting the effects of climate change.
Project description:Different populations of the same species survive different environments through local adaptation. Temperature is one of the most important driving forces that could result in local adaptation. Here, we studied the influence of extreme low temperature on the survival of two genetically and geographically distinct populations of the free-living Caenorhabditis briggsae. We found that Caenorhabditis briggsae strains of temperate origin had a cold resistant phenotype, while those originating from a tropical climate had reduced survival after cold treatment. Using this phenotypic difference between geographically diverse populations as a model for how species adapt to their local environment, we then analyzed the transcriptional profiles of two Caenorhabditis briggsae strains of tropical and temperate origin to find genes that are involved in survival after extreme cold. In summary, the response to the extreme low temperature that clearly distinguishes the temperate and tropical Caenorhabditis briggsae strains could serve as an excellent example for studying local adaption of species that show genetic separation associated with their geographical distribution.
Project description:Atlantic salmon production in Tasmania (Southern Australia) occurs near the upper limits of the species thermal tolerance. Summer water temperatures can average over 19°C over several weeks and have negative effects on performance and health. Liver tissue exerts important metabolic functions in thermal adaptation. With the aim of identifying the mechanisms underlying liver plasticity in response to chronic elevated temperature in Atlantic salmon, label-free quantitative shotgun proteomics was used to explore quantitative protein changes after 43 days of exposure to elevated temperature. A total of 277 proteins were differentially (adjusted p-value <0.05) expressed between the control (15°C) and elevated (21°C) temperature treatments. As predicted identified by Ingenuity pathway analysis (IPA), transcription and translation mechanisms, protein degradation via the proteasome, and cytoskeletal components were down-regulated at elevated temperature. In contrast, an up-regulated response was predicted identified for NRF2-mediated oxidative stress, endoplasmic reticulum stress, and amino acid degradation. The proteome response was paralleled by reduced fish condition factor and hepato-somatic index at elevated temperature . The present study provides further evidence of the interplay among different cellular machineries in a scenario of heat-induced energy deficit and oxidative stress, and refines present understanding of how Atlantic salmon cope with chronic exposure to temperature near the upper limits of thermal tolerance.
Project description:Atlantic cod (~70 g) were exposed to water temperatures of 12 and 17 degrees Celsius (flow-through system), then half the fish in each temperature group were infected with Francisella noatunensis (injection). Fish were sampled prior to temperature challenge, when water temp reached 17 degrees, and five weeks after infection. The left section of the olfactory organ was collected on RNAlater for RNA isolation and sequencing.