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Genes with expression level regulated by genotype (N2 vs CB4856) and age at old adults stage (214 hours at 24 centigrade). |
For model 2, authors used 100 permutations to estimate the FDR threshold. Per permutation, genotypes and ages were independently randomly distributed, keeping the among-gene structure intact. Then for each spot (23,232) on the array, model 2 was tested. The obtained P-values were used to estimate a threshold for each of the explanatory factors. Authors also used a genome-wide threshold of -log10 P-value = 2, which resembles an FDR of 0.072 and 0.060 for marker and the interaction age-marker for the developing worms and FDR of 0.050 and 0.065 for marker and age-marker for the aging worms. For the physiological age effect, authors used a log10 P-value = 8 in developing worms (0.012 FDR) and -log10 P-value = 6 (0.032 FDR). |
WBPaper00040858:eQTL_age_regulated_aging
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Genes with expression level regulated by genotype (N2 vs CB4856) and age at L3 larva and Late reproduction stage (96 hours at 24 centigrade). |
For model 2, authors used 100 permutations to estimate the FDR threshold. Per permutation, genotypes and ages were independently randomly distributed, keeping the among-gene structure intact. Then for each spot (23,232) on the array, model 2 was tested. The obtained P-values were used to estimate a threshold for each of the explanatory factors. Authors also used a genome-wide threshold of -log10 P-value = 2, which resembles an FDR of 0.072 and 0.060 for marker and the interaction age-marker for the developing worms and FDR of 0.050 and 0.065 for marker and age-marker for the aging worms. For the physiological age effect, authors used a log10 P-value = 8 in developing worms (0.012 FDR) and -log10 P-value = 6 (0.032 FDR). |
WBPaper00040858:eQTL_age_regulated_developing
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Genes with expression level regulated by genotype (N2 vs CB4856) at old adults stage (214 hours at 24 centigrade). |
For model 2, authors used 100 permutations to estimate the FDR threshold. Per permutation, genotypes and ages were independently randomly distributed, keeping the among-gene structure intact. Then for each spot (23,232) on the array, model 2 was tested. The obtained P-values were used to estimate a threshold for each of the explanatory factors. Authors also used a genome-wide threshold of -log10 P-value = 2, which resembles an FDR of 0.072 and 0.060 for marker and the interaction age-marker for the developing worms and FDR of 0.050 and 0.065 for marker and age-marker for the aging worms. For the physiological age effect, authors used a log10 P-value = 8 in developing worms (0.012 FDR) and -log10 P-value = 6 (0.032 FDR). |
WBPaper00040858:eQTL_regulated_aging
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Genes with expression level regulated by genotype (N2 vs CB4856) at Late reproduction stage (96 hours at 24 centigrade). |
Authors permuted transcript values and used a genome-wide threshold of log10 P-value = 2, which resembles a false discovery rate (FDR) of 0.0118. |
WBPaper00040858:eQTL_regulated_reproductive
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Genes expressed in N2. |
Expressed transcripts were identified on the basis of a Present call in 3 out of 4 N2 experiments as determined by Affymetrix MAS 5.0. |
WBPaper00025141:N2_Expressed_Genes
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Genes with expression level regulated by genotype (N2 vs CB4856) at L3 larva stage |
Authors permuted transcript values and used a genome-wide threshold of log10 P-value = 2, which resembles a false discovery rate (FDR) of 0.0129. |
WBPaper00040858:eQTL_regulated_juvenile
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Genes that showed significantly decreased experssion after 22.5 hours of treatment in 200nM delta7-dafachronic acid comparing with in ethanol vehicle control. |
To identify the differentially expressed genes, we applied Significance Analysis of Microarrays (SAM) analysis using the R package samr [46]. Genes with median false discovery <5% and fold changes >2.0 were considered differentially expressed. |
WBPaper00046548:dafachronic-acid_downregulated
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Up-regulated genes under 0.5mg/l CPF treatment at 16 centigrade. |
The Rank Product package was used to identify the differentially expressed genes between controls and treatment in each experiment. Briefly, genes were ranked based on up- or downregulation by the treatment in each experiment. Then, for each gene a combined probability was calculated as a rank product (RP). The RP values were used to rank the genes based on how likely it was to observe them by chance at that particular position on the list of differentially expressed genes. The RP can be interpreted as a p-value. To determine significance levels, the RP method uses a permutation-based estimation procedure to transform the p-value into an e-value that addresses the multiple testing problem derived from testing many genes simultaneously. Genes with a percentage of false-positives (PFP) < 0.05 were considered differentially expressed between treatments and control in each experiment. This method has the advantage to identify genes with a response to the toxicants even when the absolute effect of the response was low. Because authors used sub-lethal concentrations of the toxicants, methods that use thresholds based on absolute fold change would not identify small changes in gene expression. Moreover, RP has proved to be a robust method for comparing microarray data from different sources and experiments. |
WBPaper00037113:CPF_16C_up-regulated
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Genes expressed in embryonic motor neurons (identified by unc-4::GFP expressing cells). |
Genes called Present by MAS 5.0 in 2 out of 3 unc-4::GFP hybridizations. |
WBPaper00025141:unc-4::GFP_Expressed_Genes
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Genes with expression level regulated by genotype (N2 vs CB4856) at Old adults stage (214 hours at 24 centigrade). |
Authors permuted transcript values and used a genome-wide threshold of log10 P-value = 2, which resembles a false discovery rate (FDR) of 0.0136. |
WBPaper00040858:eQTL_regulated_old
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Genes from eat-2(ad465) animals with significantly increased expression after 72 hours of treatment on growth media with 10uM rapamycin in 2% DMSO. |
Analysis of gene expression data was carried out with the Affymetrix Transcriptome Analysis Console. Data preprocessing (using RMA normalization) and QC metrics were performed using Affymetrix Expression Console TM and manually inspected afterwards. Expression analysis was carried out for each two pairwise conditions. FDR statistical correction for multiple testing resulted in a slightly lower number of DEGs in most cases. P-value < 0.05 and fold change > 2.0 were used to determine differentially expressed genes. |
WBPaper00048989:eat-2(ad465)_rapamycin_upregulated
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Expression Pattern Group I, enriched for genes involved in transport. |
The significance (P 0.0001) of the relative age (time) was used to determine if a gene was differentially expressed between the three age (time) groups. The effect of this factor explaining gene expression differences was used to determine if the expression went up or down during the two age/time periods (t1 - t2 and t2 -t3). Authors used a permutation approach to determine the thresholds for the different mapping strategies. For each of the used models for eQTL mapping, authors used 23,000 permutations. For each permutation, authors randomly picked a spot; each spot could only be picked once. The gene expression and relative lifespan values were than randomly distributed over the RILs (and time points) and used for mapping. In this way, authors obtained a threshold for each of the explaining factors. For the single time points, authors used a FDR of 0.01 to adjust for multiple testing. The genome-wide threshold for this FDR is -log10 P = 3.8 for each of the three time points. For the combined models (t1 to t2 and t2 to t3), authors used a genome-wide threshold of -log10 P = 4, which resembles an FDR of 0.006, 0.001, and 0.006 for marker, age, and the interaction between marker and age, respectively. To determine the threshold for the single gene examples, authors used 1000 permutations as in the genome-wide threshold. The difference is that they use the gene under study in all of the permutations. The P-values for the gene specific thresholds were determined at FDR = 0.05. |
WBPaper00036286:Pattern_I
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Genes with differential expression under 0.5mg/l Chlorpyrifos (CPF) treatment at 24 centigrade. |
To identify the differentially expressed genes in each treatment authors used linear models per toxicant and temperature (gene expression = Toxicant (effect) + error). The lm function in R stats package was used to implement the linear models analysis with recommended default options. For threshold determination authors used a permutation approach. For each of the 23,232 permutations used authors randomly picked a transcript (array spot), which could only be picked once. Authors combined all the expression values of this transcript and randomly distributed them over the replicates and used them in the linear model. In this way authors obtained a threshold for each of the toxicants. Authors used a -log10 p-value 2 as common threshold for the analysis, which resembles to the following FDR per toxicant: 0.0155 for CPF at 24 centigrade, 0.0148 for DZN at 24 centigrade, 0.0168 for CPF+DZN at 24 centigrade, 0.0142 for CPF at 16 centigrade, 0.0151 for DZN at 16 centigrade, and 0.0148 for CPF+DZN, at 16 centigrade. |
WBPaper00040210:Chlorpyrifos_24C_regulated
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Genes with no change in hcf-1(-), upregulated in sir-2.1(O/E) and upregulated in daf-2(-). |
To identify the genes that show consistent and significant expression changes across the independent biological replicates of hcf-1(-) or sir-2.1(O/E), authors used Significance Analysis of Microarrays (SAM) with a stringent criteria of expected false discovery rate (FDR) set at 0%. |
WBPaper00040184:hcf-1nc_sir-2.1up_daf-2up
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