Project description:This study measured the differential expression of genes from a single clonal Daphnia pulex isolate obtained from an eutrophic flooded opencast mine near Gräfenhain (Saxony, Germany) and has been kept in the laboratory since 2002. The daphniids (50 adult animals per batch) were raised in 3-L glass beakers under a 16 h:8 h L:D photoperiod. Three-quarter of the culture medium (M4) was renewed once a week, and the animals were equally fed ad libitum with algae (Desmodesmus subspicatus; SAG 53.80, Göttingen, Germany). Long-term-acclimated animals were kept at three different temperatures (i.e., 10 ± 0.5°C, 20 ± 0.3°C, and 24 ± 0.3°C) under normoxia (Po2 ≥ 20 kPa) for at least twelve weeks. Time-resolved experiments (acute heat stress) were carried out with long-term 20°C acclimated animals, which were exposed for three different time intervals (2, 4, and 8 h) to either 30 ± 0.2°C (test conditions) or 20 ± 0.3°C (control conditions). For this, 50 animals each were rapidly transferred with a sieve (mesh size: 1.2 mm) from 20°C-medium to a set of beakers containing 30°C-medium. As control, 50 animals each were transferred from 20°C-medium to another set of beakers with 20°C-medium. Only adult female animals with a body length of 2−2.5 mm (between the base of the apical spine and the anterior part of the head) and carrying parthenogenetic eggs and embryos were used for experiments. Animals were not fed during short-term exposures. During experiments, all animals were in good physical condition. After thermal acclimation or heat exposure, animals were transferred into 1.5-ml microcentrifuge tubes and shock-frozen in liquid nitrogen after removing adhering water with a tissue paper. Samples were short-term stored at -80°C. For all experimental conditions, four independent replicates (50 animals each) were analyzed. This GEO record is for the acute heat stress temperature contrasts between animals conditioned to 20 degrees Celsius (condition 1) versus heat shock to 30 degrees Celsius (condition 2) exposed for 2 hours (treatment 1), 4 hours (treatment 2), and 8 hours (treatment 3).
Project description:This study measured the differential expression of genes from a single clonal Daphnia pulex isolate obtained from an eutrophic flooded opencast mine near Gräfenhain (Saxony, Germany) and has been kept in the laboratory since 2002. The daphniids (50 adult animals per batch) were raised in 3-L glass beakers under a 16 h:8 h L:D photoperiod. Three-quarter of the culture medium (M4) was renewed once a week, and the animals were equally fed ad libitum with algae (Desmodesmus subspicatus; SAG 53.80, Göttingen, Germany). Long-term-acclimated animals were kept at three different temperatures (i.e., 10 ± 0.5°C, 20 ± 0.3°C, and 24 ± 0.3°C) under normoxia (Po2 ≥ 20 kPa) for at least twelve weeks. Time-resolved experiments (acute heat stress) were carried out with long-term 20°C acclimated animals, which were exposed for three different time intervals (2, 4, and 8 h) to either 30 ± 0.2°C (test conditions) or 20 ± 0.3°C (control conditions). For this, 50 animals each were rapidly transferred with a sieve (mesh size: 1.2 mm) from 20°C-medium to a set of beakers containing 30°C-medium. As control, 50 animals each were transferred from 20°C-medium to another set of beakers with 20°C-medium. Only adult female animals with a body length of 2−2.5 mm (between the base of the apical spine and the anterior part of the head) and carrying parthenogenetic eggs and embryos were used for experiments. Animals were not fed during short-term exposures. During experiments, all animals were in good physical condition. After thermal acclimation or heat exposure, animals were transferred into 1.5-ml microcentrifuge tubes and shock-frozen in liquid nitrogen after removing adhering water with a tissue paper. Samples were short-term stored at -80°C. For all experimental conditions, four independent replicates (50 animals each) were analyzed. This GEO record is for the contrasts between animals conditioned to 10 degrees Celsius (condition 1) versus 20 degrees Celsius (condition 2), 10 degrees Celsius (condition 1) versus 24 degrees Celsius (condition 3), and 20 degrees Celsius (condition 2) versus 24 degrees Celsius (condition 3)
Project description:Analysis of evolved changes in transcriptional plasticity and parental effects on plasticity induced by mild heat stress in the nematode Caenorhabditis remanei. Results of this study highlight the importance of the broad environmental context of an organism and its influence on phenotypic plasticity, parental effects, and evolutionary responses. mRNA profiles of ancestral and two experimentally evolved populations of C. remanei. Parents of the sampled worms were raised at either 20°C or 30°C, then the resulting embryos were divided and reared at either 20°C or 30°C prior to collection (as L1 larvae). 6 replicates/larval temperature for each population if the parents were raised at 20°C, and 2 replicates/larval temperature for each population if the parents were raised at 30°C.
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.
Project description:Traditionally, the study of evolution has focused on heritable variation, because selection on non-heritable phenotypic variation was deemed non-important for its inability to cause evolutionary responses such as diversification of lineages. Recently however, it has been suggested that also environmentally induced phenotypic variation such as phenotypic plasticity can play an important role in adaptive responses resulting in diversification. The purpose of this study is to investigate the importance of phenotypic plasticity for the diversification of lineages, using life history, morphological traits, and genomic profiling during post embryonic development in plastic and non-plastic genotypes of the common frog Rana temporaria. Six animals each originating from four different islands were reared in either constant or reduced water conditions and hepatic mRNA levels of Gosner stage 37 animals evaluated by MAGEX DNA array analysis.