Locally adapted populations of a copepod species exhibit starkly different gene expression responses to different thermal environments
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ABSTRACT:
ORGANISM(S): Tigriopus californicus
PROVIDER: GSE80737 | GEO | 2016/07/25
REPOSITORIES: GEO
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Project description:This study aimed at measuring transcriptome-wide gene expression in four populations of the copepod T. californicus. Populations were exposed to two different thermal regime, a variable 20-28 degree and a constant 20 degree followed by a one-time stress at 28 degrees. RNA was extracted at 20 and 28 degrees for all populations from all thermal regimes. Transcriptome-wide gene expression was measured, and differentially expressed genes were determined for all populations for the different temperature combinations. The results show that each populations responds to the changes in temperature in a drastically different manner (in terms of gene expression), which can have implications regarding the way these and other organisms will respond to climate change. Two southern and two northern populations of Tigriopus californicus were exposed to a variable 20-28 degree and a constant 20 degree followed by a one-time stress at 28 degrees. RNA was extracted at 20 and 28 degrees for all populations from all thermal regimes. mRNA profiles were generated by 100bp single end sequencing in the Illumina HiSeq 2000 and 2500, with one replicate per population per treatment.
2016-07-25 | E-GEOD-80737 | biostudies-arrayexpress
Project description:Background: Geographic variation in the thermal environment impacts a broad range of biochemical and physiological processes and can be a major selective force leading to local population adaptation. In the intertidal copepod Tigriopus californicus, populations along the coast of California show differences in thermal tolerance that are consistent with adaptation, i.e., southern populations withstand thermal stresses that are lethal to northern populations. To understand the genetic basis of these physiological differences, we use an RNA-seq approach to compare genome-wide patterns of gene expression in two populations known to differ in thermal tolerance. Results: Observed differences in gene expression between the southern (San Diego) and the northern (Santa Cruz) populations included both the number of affected loci as well as the identity of these loci. However, the most pronounced differences concerned the amplitude of up-regulation of genes producing heat shock proteins (Hsps) and genes involved in ubiquitination and proteolysis. Cuticle genes were up-regulated in SD but down-regulated in SC, and mitochondrial genes were downregulated in both populations. Among the hsp genes, orthologous pairs show markedly different thermal responses as the amplitude of hsp response was greatly elevated in the San Diego population, most notably in members of the hsp70 gene family. There was no evidence of accelerated evolution at the sequence level for hsp genes. Conclusions: Marked changes in gene expression were observed in response to acute sublethal thermal stress in the copepod T. californicus. Although some qualitative differences were observed between populations (e.g., cuticle gene regulation), the most pronounced differences involved the magnitude of induction of numerous hsp and ubiquitin genes. These differences in gene expression suggest that evolutionary divergence in the regulatory pathway(s) involved in acute temperature stress may offer at least a partial explanation of latitudinal trends in thermal tolerance observed in Tigriopus. For each population, ~600 copepods were split into two equal samples, one for control and one for treatment. Each sample was placed in a 50 mL Falcon tube containing 30 mL filtered seawater. After equilibrating samples to 20 degrees C, each tube was immersed in water bath at its target temperature (control: 20 C; treatment: 35 C) for one hour, and then immersed at 20 C for one hour for recovery. Copepods were then collected in a net mesh and quickly transferred to a tube containing 5 mL Tri-reagent for standard RNA extraction.
2012-09-11 | E-GEOD-38546 | biostudies-arrayexpress
Project description:Background: Geographic variation in the thermal environment impacts a broad range of biochemical and physiological processes and can be a major selective force leading to local population adaptation. In the intertidal copepod Tigriopus californicus, populations along the coast of California show differences in thermal tolerance that are consistent with adaptation, i.e., southern populations withstand thermal stresses that are lethal to northern populations. To understand the genetic basis of these physiological differences, we use an RNA-seq approach to compare genome-wide patterns of gene expression in two populations known to differ in thermal tolerance. Results: Observed differences in gene expression between the southern (San Diego) and the northern (Santa Cruz) populations included both the number of affected loci as well as the identity of these loci. However, the most pronounced differences concerned the amplitude of up-regulation of genes producing heat shock proteins (Hsps) and genes involved in ubiquitination and proteolysis. Cuticle genes were up-regulated in SD but down-regulated in SC, and mitochondrial genes were downregulated in both populations. Among the hsp genes, orthologous pairs show markedly different thermal responses as the amplitude of hsp response was greatly elevated in the San Diego population, most notably in members of the hsp70 gene family. There was no evidence of accelerated evolution at the sequence level for hsp genes. Conclusions: Marked changes in gene expression were observed in response to acute sublethal thermal stress in the copepod T. californicus. Although some qualitative differences were observed between populations (e.g., cuticle gene regulation), the most pronounced differences involved the magnitude of induction of numerous hsp and ubiquitin genes. These differences in gene expression suggest that evolutionary divergence in the regulatory pathway(s) involved in acute temperature stress may offer at least a partial explanation of latitudinal trends in thermal tolerance observed in Tigriopus.
2012-09-11 | GSE38546 | GEO
Project description:Temperature profoundly affects biological systems across all levels of organization. Over generations, species become evolutionarily adapted to specific thermal environments. In addition to evolved adaptive differences, individuals may reversibly modify their phenotype within their lifetimes in response to different thermal environments in a process termed phenotypic plasticity. The interaction between, evolutionary adaptation and phenotypic plasticity is complex and contentious. We utilize Fundulus glycolytic muscle physiology to address this interaction. We conducted a microarray analysis of muscle gene expression using three populations of Fundulus acclimated to three different temperatures. A phylogenetic comparative analysis among populations from different thermal environments demonstrates adaptive variation in mRNA expression for 186 genes. Sixty-seven genes had significant differences in mRNA expression in response to thermal acclimation. Interestingly, evolutionary adaptation and phenotypic plasticity appear to operate primarily orthogonally: few genes (although more than expected by chance alone) exhibit both adaptive variation and phenotypic plasticity. The magnitude and function of the adaptive variation in gene expression is dependent on acclimation temperature (e.g., more genes have adaptive differences at 12° and 28°C than at 20°C), demonstrating the importance of gene-by-environment interactions. Finally, a functional analysis of gene expression provides novel, testable hypotheses regarding adaptation of muscle physiology.
2013-07-30 | GSE49335 | GEO
Project description:Here, we investigate the genetic mechanisms that underlie thermal specialization of closely-related vibrios isolated from coastal water at the Beaufort Inlet (Beaufort, NC, USA). This location experiences large seasonal temperature fluctuations (annual range of ~20°C), and a clear seasonal shift in vibrio diversity has been observed (Yung et al. 2015). This previous study suggested that the mechanisms of thermal adaptation apparently differ based on evolutionary timescale: shifts in the temperature of maximal growth occur between deeply branching clades but the shape of the thermal performance curve changes on shorter time scales (Yung et al. 2015). The observed thermal specialization in vibrio populations over relatively short evolutionary time scales indicates that few genes or cellular processes may contribute to the differences in thermal performance between populations. In order to understand the molecular mechanisms that underlie adaptation to local thermal regimes in environmental vibrio populations, we employ genomic and transcriptomic approaches to examine transcriptomic changes that occur within strains grown at their thermal optima and under heat and cold stress. Moreover, we compare two closely-related strains with different laboratory thermal preferences to identify in situ evolutionary responses to different thermal environments in genome content and alleles as well as gene expression.
2018-07-31 | GSE83396 | GEO
Project description:In this study we use nimblegen high-density arrays to examine gene expression regulation in a common-garden experiment varying thermal environments. We report genome-wide patterns of gene expression in two heat tolerant southern and two heat-sensitive northern clones of Daphnia pulex exposed to either optimal (18°C) or substressful (28°C) temperatures. Four competitive hybridizations of heat tolerant clones BW102 (hereafter B) and KSP3 (hereafter K), and heat sensitive clones EB1 (hereafter E) and CHQ3 (hereafter C) in response to thermal stress of either 18 degrees Celcius (here after 18) or 28 degrees (hereafter 28) in a loop design where each hybridization was replicated four times with two dye-swaps nested in each set of replicates.
2014-10-02 | E-GEOD-53692 | biostudies-arrayexpress
Project description:Thermal stress is a serious and growing challenge facing Chinook salmon (Oncorhynchus tshawytscha) living in the southern portion of their native range. River alterations have increased the likelihood that juveniles will be exposed to warm water temperatures during their freshwater life stage, which can negatively impact survival, growth, and development and poses a threat to dwindling salmon populations. In order to better understand how acute thermal stress affects the biology of salmon, we performed a transcriptional analysis of gill tissue from unacclimated Chinook juveniles exposed to short periods at water temperatures ranging from ideal to potentially lethal. Reverse transcribed RNA libraries were sequenced on the Illumina HiSeq2000 platform and a de novo reference transcriptome was created. Differentially expressed transcripts were annotated using Blast2GO and relevant gene clusters were identified. Fifty-five fish were randomly assigned to one of five treatment groups and were allowed to acclimate at 12 degrees C in the experimental chambers overnight. Treatments consisted of a three-hour water bath at 15 degrees C, 18 degrees C, 21 degrees C or 25 degrees C degrees, followed by one hour of recovery at 12 degrees C. The experimental chambers were moved to water baths held at a constant temperature, facilitating very rapid change in the temperature experienced by the fish. Controls were handled identically to the other four treatment groups, but remained at 12 degrees C. Three replicates were performed on consecutive days. RNA from the 11 individuals in each treatment group were proportionally pooled and used to create 15 illumina libraries.
2015-07-25 | E-GEOD-59756 | biostudies-arrayexpress
Project description:This is a study to characterize gene expression profiles in stored Russet Burbank potato tubers. Tubers were harvested from commercial fields in the central sands region of Wisconsin in the fall of 2006. The tubers were put into storage at 55 degrees F for preconditioning and wound healing. Shortly after the temperature of the storage bin began to decrease, uniform, healthy tubers were selected for use in this microarray analysis. Tubers were at 53.6 degrees F at this time, and pieces of starch-storing tissue were collected for use as the reference sample. Other tubers were moved to temperature-controlled lockers and these were cooled gradually to either 48 or 40 degrees F following industry standard procedures. The expectation was that tubers held at 48 degrees would not have a significant accumulation of glucose and fructose, but that tubers cooled to 40 degrees would undergo low temperature sweetening and accumulate glucose and fructose to a degree that is unsuitable for processing. Three weeks later, when the locker temperatures were 48 degrees F and 41.5 degrees F, tissue samples were collected for RNA analysis. After another three weeks, samples were collected from tubers at 48 degrees F and 40 degrees F. At that time some tubers were moved from the 48 degree locker to the 40 degree locker in order to see if gene expression changes observed as a result of gradual cooling are similar to those that occur following a sudden decrease in temperature. Three weeks later, samples were collected from tubers held at 48 degrees F, tubers held at 40 degrees F, and from the tubers that were moved from 48 to 40 degrees F. At this time another set of tubers was transferred from 48 degrees to 40 degrees. Three weeks later the last samples were harvested from tubers held at 48 degrees F, from tubers held at 48 degrees F and from tubers that were transferred three weeks prior from 48 to 40 degrees. RNA was isolated from tissue extracted from three tubers. Keywords: Reference design
2008-02-13 | GSE10483 | GEO
Project description:To investigate the molecular basis of fluctuating temperature induced phenotypic plasticity, we ran genome-wide transcriptomic analysis on Drosophila melanogaster subjected to acclimation at constant (19 +/- 0 degree Celcius) and fluctuating (19 +/- 8 degree Celcius) temperatures and contrasted the induction of molecular mechanisms in adult males, adult females, and larvae. We investigated whether fluctuations act by permanently activating the involved mechanisms, or whether fluctuations repeatedly activate and repress mechanisms, during the hot (or heating) and the cold (or cooling) phase of thermal fluctuations. We show that adult flies acclimated to fluctuating temperatures tolerate high temperatures better than the constant temperature acclimated controls. Differential gene expression indicated that responses to thermal variability rely partly on life stage and sex specific mechanisms. Our results show that some of the involved mechanisms were permanently activated, while others tracked the thermal fluctuations. Further, for a number of genes, fluctuating temperature resulted in canalization of gene expression. Molecular mechanisms related to environmental sensing and chromatin reorganization seems to be important components of adaptive responses to thermal variability.
2022-04-04 | GSE150450 | GEO
Project description:Changes in environmental temperature can profoundly change species habitats and result in populations facing suboptimal environments. Many aquatic organisms are restricted in terms of migration by their habitat requirements. Also due to anthropogenic migration barriers (both physical as well as chemical), organisms are often left with no choice but to acclimate (or, in the long run, adapt) to their changing environment. The scope of this study is to investigate thermal acclimation in zebrafish by combining data from several levels of biological organization. Zebrafish were acclimated to a higher temperature (8°C increase compared to controls) or a lower temperature (8°C decrease compared to controls) in an acute as well as a prolonged and a chronic scenario (4, 14 and 28 days). General condition of the fish was assessed by determining organismal (condition factor) and biochemical (energy homeostasis) parameters. Data at the transcriptome level (using printed oligonucleotide microarrays containing 15,208 probes and real time PCR) were applied to clarify the mechanisms underlying the thermal acclimation response in zebrafish.
2010-08-28 | GSE17756 | GEO