Project description:Plants display remarkable developmental and phenotypic plasticity in order to adapt to their environment. It has long been postulated that epigenetics plays a key role in these processes, but with one or two exceptions, solid evidence for the role of epigenetic variation in these processes is lacking. A key impediment to understanding these processes is the lack of information on the extent of epigenetic variation and how it relates to genetic and phenotypic variation in natural population, both over the lifecycle of an individual, and over evolutionary time. Here we show that genetic variants under selection in the north of Sweden appear to drive variation in DNA methylation, which in turn is highly correlated with local climate. Selective sweeps and genetic variants associated with adaptation to the local environment have previously been identified within the Swedish Arabidopsis population. Our finding that they harbour variants responsible for climate associated epigenetic variation strongly supports the role of epigenetic processes in local adaptation. These findings provide a basis for further dissecting the role of epigenetics in local adaptation at the molecular level Bisulfite sequencing of 113 F2 crosses between T550 and Brosarp-11-135.
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:Here we investigate DNA methylation variation in Swedish Arabidopsis thaliana accessions, demonstrating that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is highly correlated with climate of origin and associated with genetic polymorphism in trans that shows evidence of local adaptation. While genome-wide surveys of naturally occurring DNA methylation have been published previously, the degree of genetic control revealed here is unprecedented. Furthermore, the observation that DNA methylation is associated with climate, and is apparently adaptively important, is completely novel. Bisulfite sequencing of 152 Swedish Arabidobsis accessions grown at 10 C and 121 grown at 16 C
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. Previously we sequenced and assembled whole larval transcriptome ESTs sourced from pooled central-population individuals subjected to environmental stressors (see O'Neil et al., 2008). From these assemblies custom Nimblegen microarrays were designed (Nimblegen, Inc.), representing 34,609 putative gene sequences for E. propertius (submitted separately) and 25,735 putative gene sequences for P. zelicaon (this submission). Probe designs sought 5 representative 60mer probes for E.propertius and 4 representative probes for P. zelicaon. Messenger RNA was was sampled from multiple individuals of each experimental group and pooled before being converted to cDNA and hybridized to technical replicate microarrays. Three technical replicates for each experimental group were used, for a total of 12 microarrays (per species). Microarray data were log2 transformed and quintile-normalized (Bolstad et al. 2003) on a per-species basis.
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. Previously we sequenced and assembled whole larval transcriptome ESTs sourced from pooled central-population individuals subjected to environmental stressors (see O'Neil et al., 2008). From these assemblies custom Nimblegen microarrays were designed (Nimblegen, Inc.), representing 34,609 putative gene sequences for E. propertius (this submission) and 25,735 putative gene sequences for P. zelicaon (submitted seperately). Probe designs sought 5 representative 60mer probes for E.propertius and 4 representative probes for P. zelicaon. Messenger RNA was was sampled from multiple individuals of each experimental group and pooled before being converted to cDNA and hybridized to technical replicate microarrays. Three technical replicates for each experimental group were used, for a total of 12 microarrays (per species). Microarray data were log2 transformed and quintile-normalized (Bolstad et al. 2003) on a per-species basis.
Project description:Plants display remarkable developmental and phenotypic plasticity in order to adapt to their environment. It has long been postulated that epigenetics plays a key role in these processes, but with one or two exceptions, solid evidence for the role of epigenetic variation in these processes is lacking. A key impediment to understanding these processes is the lack of information on the extent of epigenetic variation and how it relates to genetic and phenotypic variation in natural population, both over the lifecycle of an individual, and over evolutionary time. Here we show that genetic variants under selection in the north of Sweden appear to drive variation in DNA methylation, which in turn is highly correlated with local climate. Selective sweeps and genetic variants associated with adaptation to the local environment have previously been identified within the Swedish Arabidopsis population. Our finding that they harbour variants responsible for climate associated epigenetic variation strongly supports the role of epigenetic processes in local adaptation. These findings provide a basis for further dissecting the role of epigenetics in local adaptation at the molecular level
2015-03-28 | GSE65685 | GEO
Project description:Parallel local adaptation to climate driven by introgression in oak species
Project description:Here we investigate DNA methylation variation in Swedish Arabidopsis thaliana accessions, demonstrating that methylation of transposable elements is temperature sensitive and associated with genetic polymorphism in both cis and trans, whereas gene body methylation is highly correlated with climate of origin and associated with genetic polymorphism in trans that shows evidence of local adaptation. While genome-wide surveys of naturally occurring DNA methylation have been published previously, the degree of genetic control revealed here is unprecedented. Furthermore, the observation that DNA methylation is associated with climate, and is apparently adaptively important, is completely novel.
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.