findmarkers volcano plot
Help! I would like to create a volcano plot to compare differentially expressed genes (DEGs) across two samples- a "before" and "after" treatment. The analyses presented here have illustrated how different results could be obtained when data were analysed using different units of analysis. The null and alternative hypotheses for the i-th gene are H0i:i2=0 and H0i:i20, respectively. Step 3: Create a basic volcano plot. Third, the proposed model also ignores many aspects of the gene expression distribution in favor of simplicity. In another study, mixed models were found to be superior alternatives to both pseudobulk and marker detection methods (Zimmerman et al., 2021). ADD REPLY link 18 months ago by Kevin Blighe 84k 0. ## [28] dplyr_1.1.1 crayon_1.5.2 jsonlite_1.8.4 One such subtype, defined by expression of CD66, was further processed by sorting basal cells according to detection of CD66 and profiling by bulk RNA-seq. Carver College of Medicine, University of Iowa. make sure label exists on your cells in the metadata corresponding to treatment (before- and after-), You will be returned a gene list of pvalues + logFc + other statistics. ## [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C If we omit DESeq2, which seems to be an outlier, the other six methods form two distinct clusters, with cluster 1 composed of wilcox, NB, MAST and Monocle, and cluster 2 composed of subject and mixed. ## [103] jquerylib_0.1.4 RcppAnnoy_0.0.20 data.table_1.14.8 healthy versus disease), an additional layer of variability is introduced. Results for alternative performance measures, including receiver operating characteristic (ROC) curves, TPRs and false positive rates (FPRs) can be found in Supplementary Figures S7 and S8. Tried. Step 1: Set up your script. Step-by-step guide to create your volcano plot. For higher numbers of differentially expressed genes (pDE > 0.01), the subject method had lower NPV values when = 0.5 and similar or higher NPV values when > 0.5. The study by Zimmerman et al. In stage ii, we assume that we have not measured cell-level covariates, so that variation in expression between cells of the same type occurs only through the dispersion parameter ij2. Was this translation helpful? In summary, here we (i) suggested a modeling framework for scRNA-seq data from multiple biological sources, (ii) showed how failing to account for biological variation could inflate the FDR of DS analysis and (iii) provided a formal justification for the validity of pseudobulking to allow DS analysis to be performed on scRNA-seq data using software designed for DS analysis of bulk RNA-seq data (Crowell et al., 2020; Lun et al., 2016; McCarthy et al., 2017). ## [7] LC_PAPER=en_US.UTF-8 LC_NAME=C ## [25] ggrepel_0.9.3 textshaping_0.3.6 xfun_0.38 Figure 5d shows ROC and PR curves for the three scRNA-seq methods using the bulk RNA-seq as a gold standard. Supplementary Table S2 contains performance measures derived from the ROC and PR curves. ## [73] fastmap_1.1.1 yaml_2.3.7 ragg_1.2.5 Well demonstrate visualization techniques in Seurat using our previously computed Seurat object from the 2,700 PBMC tutorial. (c) Volcano plots show results of three methods (subject, wilcox and mixed) used to identify CD66+ and CD66- basal cell marker genes. Further, subject has the highest AUPR (0.21) followed by mixed (0.14) and wilcox (0.08). We will create a volcano plot colouring all significant genes. Simply add the splitting variable to object, # metadata and pass it to the split.by argument, # SplitDotPlotGG has been replaced with the `split.by` parameter for DotPlot, # DimPlot replaces TSNEPlot, PCAPlot, etc. They also thank Paul A. Reyfman and Alexander V. Misharin for sharing bulk RNA-seq data used in this study. To better illustrate the assumptions of the theorem, consider the case when the size factor sjcis the same for all cells in a sample j and denote the common size factor as sj*. It sounds like you want to compare within a cell cluster, between cells from before and after treatment. (Zimmerman et al., 2021). ## [61] labeling_0.4.2 rlang_1.1.0 reshape2_1.4.4 (b) AT2 cells and AM express SFTPC and MARCO, respectively. ## [115] MASS_7.3-56 rprojroot_2.0.3 withr_2.5.0 Consider a purified cell type (PCT) study design, in which many cells from a cell type of interest could be isolated and profiled using bulk RNA-seq. . Theorem 1 provides a straightforward approach to estimating regression coefficients i1,,iR, testing hypotheses and constructing confidence intervals that properly account for variation in gene expression between subjects. Our study highlights user-friendly approaches for analysis of scRNA-seq data from multiple biological replicates. Default is 0.25. ## [97] Matrix_1.5-3 vctrs_0.6.1 pillar_1.9.0 We have developed the software package aggregateBioVar (available on Bioconductor) to facilitate broad adoption of pseudobulk-based DE testing; aggregateBioVar includes a detailed vignette, has low code complexity and minimal dependencies and is highly interoperable with existing RNA-seq analysis software using Bioconductor core data structures (Fig. To characterize these sources of variation, we consider the following three-stage model: In stage i, variation in expression between subjects is due to differences in covariates via the regression function qij and residual subject-to-subject variation via the dispersion parameter i. This can, # be changed with the `group.by` parameter, # Use community-created themes, overwriting the default Seurat-applied theme Install ggmin, # with remotes::install_github('sjessa/ggmin'), # Seurat also provides several built-in themes, such as DarkTheme; for more details see, # Include additional data to display alongside cell names by passing in a data frame of, # information Works well when using FetchData, ## [1] "AAGATTACCGCCTT" "AAGCCATGAACTGC" "AATTACGAATTCCT" "ACCCGTTGCTTCTA", # Now, we find markers that are specific to the new cells, and find clear DC markers, ## p_val avg_log2FC pct.1 pct.2 p_val_adj, ## FCER1A 3.239004e-69 3.7008561 0.800 0.017 4.441970e-65, ## SERPINF1 7.761413e-36 1.5737896 0.457 0.013 1.064400e-31, ## HLA-DQB2 1.721094e-34 0.9685974 0.429 0.010 2.360309e-30, ## CD1C 2.304106e-33 1.7785158 0.514 0.025 3.159851e-29, ## ENHO 5.099765e-32 1.3734708 0.400 0.010 6.993818e-28, ## ITM2C 4.299994e-29 1.5590007 0.371 0.010 5.897012e-25, ## [1] "selected" "Naive CD4 T" "Memory CD4 T" "CD14+ Mono" "B", ## [6] "CD8 T" "FCGR3A+ Mono" "NK" "Platelet", # LabelClusters and LabelPoints will label clusters (a coloring variable) or individual points, # Both functions support `repel`, which will intelligently stagger labels and draw connecting, # lines from the labels to the points or clusters, ## Platform: x86_64-pc-linux-gnu (64-bit), ## BLAS: /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3, ## LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/liblapack.so.3, ## [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C, ## [3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8, ## [5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8, ## [7] LC_PAPER=en_US.UTF-8 LC_NAME=C, ## [9] LC_ADDRESS=C LC_TELEPHONE=C, ## [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C, ## [1] stats graphics grDevices utils datasets methods base, ## [1] patchwork_1.1.2 ggplot2_3.4.1, ## [3] thp1.eccite.SeuratData_3.1.5 stxBrain.SeuratData_0.1.1, ## [5] ssHippo.SeuratData_3.1.4 pbmcsca.SeuratData_3.0.0, ## [7] pbmcMultiome.SeuratData_0.1.2 pbmc3k.SeuratData_3.1.4, ## [9] panc8.SeuratData_3.0.2 ifnb.SeuratData_3.1.0, ## [11] hcabm40k.SeuratData_3.0.0 bmcite.SeuratData_0.3.0, ## [13] SeuratData_0.2.2 SeuratObject_4.1.3. Cons: Then the regression model from Section 2.1 simplifies to logqij=i1+i2xj2. Plotting multiple plots was previously achieved with the CombinePlot() function. Because pseudobulk methods operate on gene-by-cell count matrices, they are broadly applicable to various single-cell technologies. (d) ROC and PR curves for subject, wilcox and mixed methods using bulk RNA-seq as a gold standard. Supplementary Figure S11 shows cumulative distribution functions (CDFs) of permutation P-values and method P-values. First, the CF and non-CF labels were permuted between subjects. With Seurat, all plotting functions return ggplot2-based plots by default, allowing one to easily capture and manipulate plots just like any other ggplot2-based plot. Suppose that cell-level variance ij20. ## [10] digest_0.6.31 htmltools_0.5.5 fansi_1.0.4 ## [40] abind_1.4-5 scales_1.2.1 spatstat.random_3.1-4 Hi, I am a novice in analyzing scRNAseq data. ## [37] gtable_0.3.3 leiden_0.4.3 future.apply_1.10.0 It is important to emphasize that the aggregation of counts occurs within cell types or cell states, so that the advantages of single-cell sequencing are retained. As in Section 3.5, in the bulk RNA-seq, genes with adjusted P-values less than 0.05 and at least a 2-fold difference in gene expression between healthy and IPF are considered true positives and all others are considered true negatives. #' @param output_dir The relative directory that will be used to save results. baseplot <- DimPlot (pbmc3k.final, reduction = "umap") # Add custom labels and titles baseplot + labs (title = "Clustering of 2,700 PBMCs") In order to determine the reliability of the unadjusted P-values computed by each method, we compared them to the unadjusted P-values obtained from a permutation test. I have successfully installed ggplot, normalized my datasets, merged the datasets, etc., but what I do not understand is how to transfer the sequencing data to the ggplot function. The volcano plot for the subject method shows three genes with adjusted P-value <0.05 (-log 10 (FDR) > 1.3), whereas the other six methods detected a much larger number of genes. If a gene was not differentially expressed, the value of i2 was set to 0. sessionInfo()## R version 4.2.0 (2022-04-22) A software package, aggregateBioVar, is freely available on Bioconductor (https://www.bioconductor.org/packages/release/bioc/html/aggregateBioVar.html) to accommodate compatibility with upstream and downstream methods in scRNA-seq data analysis pipelines. Further, they used flow cytometry to isolate alveolar type II (AT2) cell and alveolar macrophage (AM) fractions from the lung samples and profiled these PCTs using bulk RNA-seq. This figure suggests that the methods that account for between subject differences in gene expression (subject and mixed) will detect different sets of genes than the methods that treat cells as the units of analysis. (a) AUPR, (b) PPV with adjusted P-value cutoff 0.05 and (c) NPV with adjusted P-value cutoff 0.05 for 7 DS analysis methods. True positives were identified as those genes in the bulk RNA-seq analysis with FDR<0.05 and |log2(CD66+/CD66)|>1. We identified cell types, and our DS analyses focused on comparing expression profiles between large and small airways and CF and non-CF pigs. First, in a simulation study, we show that when the gene expression distribution of a population of cells varies between subjects, a nave approach to differential expression analysis will inflate the FDR. Four of the methods were applications of the FindMarkers function in the R package Seurat (Butler et al., 2018; Satija et al., 2015; Stuart et al., 2019) with different options for the type of test performed: for the method wilcox, cell counts were normalized, log-transformed and a Wilcoxon rank sum test was performed for each gene; for the method NB, cell counts were modeled using a negative binomial generalized linear model; for the method MAST, cell counts were modeled using a hurdle model based on the MAST software (Finak et al., 2015) and for the method DESeq2, cell counts were modeled using the DESeq2 software (Love et al., 2014). Andrew L Thurman, Jason A Ratcliff, Michael S Chimenti, Alejandro A Pezzulo, Differential gene expression analysis for multi-subject single-cell RNA-sequencing studies with aggregateBioVar, Bioinformatics, Volume 37, Issue 19, 1 October 2021, Pages 32433251, https://doi.org/10.1093/bioinformatics/btab337. ## [91] tibble_3.2.1 bslib_0.4.2 stringi_1.7.12 We performed DS analysis using the same seven methods as Section 3.1. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, https://doi.org/10.1093/bioinformatics/btab337, https://www.bioconductor.org/packages/release/bioc/html/aggregateBioVar.html, https://creativecommons.org/licenses/by/4.0/, Receive exclusive offers and updates from Oxford Academic, Academic Pulmonary Sleep Medicine Physician Opportunity in Scenic Central Pennsylvania, MEDICAL MICROBIOLOGY AND CLINICAL LABORATORY MEDICINE PHYSICIAN, CLINICAL CHEMISTRY LABORATORY MEDICINE PHYSICIAN. We can then change the identity of these cells to turn them into their own mini-cluster. The wilcox, MAST and Monocle methods had intermediate performance in these nine settings. Seurat has four tests for differential expression which can be set with the test.use parameter: ROC test ("roc"), t-test ("t"), LRT test based on zero-inflated data ("bimod", default), LRT test based on tobit-censoring models ("tobit") The ROC test returns the 'classification power' for any individual marker (ranging from 0 . As scRNA-seq studies grow in scope, due to technological advances making these studies both less labor-intensive and less expensive, biological replication will become the norm. Theorem 1: The expected value of Kij is ij=sjqij. Define Kijc to be the count for gene i in cell ccollected from subject j, and a size factorsjc related to the amount of information collected from cell c in subject j (i=1,G; c=1,,Cj;j=1,,n). . ## [106] cowplot_1.1.1 irlba_2.3.5.1 httpuv_1.6.9 ## [52] ellipsis_0.3.2 ica_1.0-3 farver_2.1.1 Specifically, the CDFs are in high agreement for the subject method in the range of P-values from 0 to 0.2, whereas the mixed method has a slight inflation of small P-values in the same range compared to the permutation test. In contrast, single-cell experiments contain an additional source of biological variation between cells. Supplementary Figure S12b shows the top 50 genes for each method, defined as the genes with the 50 smallest adjusted P-values. # S3 method for default FindMarkers( object, slot = "data", counts = numeric (), cells.1 = NULL, cells.2 = NULL, features = NULL, logfc.threshold = 0.25, test.use = "wilcox", min.pct = 0.1, min.diff.pct = -Inf, verbose = TRUE, only.pos = FALSE, max.cells.per.ident = Inf, random.seed = 1, latent.vars = NULL, min.cells.feature = 3, min.cells.group First, a random proportion of genes, pDE, were flagged as differentially expressed. Here, we introduce a mathematical framework for modeling different sources of biological variation introduced in scRNA-seq data, and we provide a mathematical justification for the use of pseudobulk methods for DS analysis. ## [46] xtable_1.8-4 reticulate_1.28 ggmin_0.0.0.9000 d Volcano plots showing DE between T cells from random groups of unstimulated controls drawn . 5c). disease and intervention), (ii) variation between subjects, (iii) variation between cells within subjects and (iv) technical variation introduced by sampling RNA molecules, library preparation and sequencing. Figure 3(b and c) show the PPV and negative predictive value (NPV) for each method and simulation setting under an adjusted P-value cutoff of 0.05. Specifically, if Kijc is the count of gene i in cell c from pig j, we defined Eijc=Kijc/i'Ki'jc to be the normalized expression for cell c from subject j and Eij=cKijc/i'cKi'jc to be the normalized expression for subject j. Yes, you can use the second one for volcano plots, but it might help to understand what it's implying. provides an argument for using mixed models over pseudobulk methods because pseudobulk methods discovered fewer differentially expressed genes. ## ## other attached packages: We then compare multiple differential expression testing methods on scRNA-seq datasets from human samples and from animal models. See Supplementary Material for brief example code demonstrating the usage of aggregateBioVar. The cluster contains hundreds of computation nodes with varying numbers of processor cores and memory, but all jobs were submitted to the same job queue, ensuring that the relative computation times for these jobs were comparable. The following equations are identical: . Before you start. data("pbmc_small") # Find markers for cluster 2 markers <- FindMarkers(object = pbmc_small, ident.1 = 2) head(x = markers) # Take all cells in cluster 2, and find markers that separate cells in the 'g1' group (metadata # variable 'group') markers <- FindMarkers(pbmc_small, ident.1 = "g1", group.by = 'groups', subset.ident = "2") head(x = markers) # Pass 'clustertree' or an object of class . Supplementary Figure S13 shows concordance between adjusted P-values for each method. In the bulk RNA-seq, genes with adjusted P-values less than 0.05 and at least a 2-fold difference in gene expression between CD66+ and CD66-basal cells are considered true positives and all others are considered true negatives. All seven methods identify two distinct groups of genes: those with higher average expression in large airways and those with higher average expression in small airways. run FindMarkers on your processed data, setting ident.1 and ident.2 to correspond to before- and after- labelled cells; You will be returned a gene list of pvalues + logFc + other statistics. Comparison of methods for detection of CD66+ and CD66- basal cell markers from human trachea. https://satijalab.org/seurat/articles/de_vignette.html. The subject and mixed methods are composed of genes that have high inter-group (CF versus non-CF) and low intra-group (between subject) variability, whereas the wilcox, NB, MAST, DESeq2 and Monocle methods tend to be sensitive to a highly variable gene expression pattern from the third CF pig. Let Gammaa,b denote the gamma distribution with shape parameter a and scale parameter b, Poissonm denote the Poisson distribution with mean m and XY denote the conditional distribution of random variable X given random variable Y. Each panel shows results for 100 simulated datasets in one simulation setting. (e and f) ROC and PR curves for subject, wilcox and mixed methods using bulk RNA-seq as a gold standard for (e) AT2 cells and (f) AM. Here is the Volcano plot: I read before that we are not allowed to do the differential gene expression using the integrated data. We designed a simulation study to examine characteristics of using subjects or cells as units of analysis for DS testing under data simulated from the proposed model. For each subject, the number of cells and numbers of UMIs per cell were matched to the pig data. The marker genes list can be a list or a dictionary. a, Volcano plot of RNA-seq data from bulk hippocampal tissue from 8- to 9-month-old P301S transgenic and non-transgenic mice (Wald test). Further, the cell-level variance and subject-level variance parameters were matched to the pig data. ", I have seen tutorials on the web, but the data there is not processed the same as how I have been doing following the Satija lab method, and, my files are not .csv, but instead are .tsv. For the AM cells (Fig. ## [109] R6_2.5.1 promises_1.2.0.1 KernSmooth_2.23-20 In addition, it will plot either 'umap', 'tsne', or, # DoHeatmap now shows a grouping bar, splitting the heatmap into groups or clusters. ## [4] lazyeval_0.2.2 sp_1.6-0 splines_4.2.0 Red and blue dots represent genes with a log 2 FC (fold . We will call genes significant here if they have FDR < 0.01 and a log2 fold change of 0.58 (equivalent to a fold-change of 1.5). These approaches will likely yield better type I and type II error rate control, but as we saw for the mixed method in our simulation, the computation times can be substantially longer and the computational burden of these methods scale with the number of cells, whereas the pseudobulk method scales with the number of subjects. yale law professor judith resnik challenger, lauren jones wave 3 husband, wa government household electricity credit final adjustment,