## ----load-libs, message = FALSE, warning = FALSE----------------------------- library(cowplot) library(dplyr) library(reshape2) library(muscat) library(purrr) library(scater) library(SingleCellExperiment) ## ----prepSim------------------------------------------------------------------ # estimate simulation parameters data(example_sce) ref <- prepSim(example_sce, verbose = FALSE) # only samples from `ctrl` group are retained table(ref$sample_id) # cell parameters: library sizes sub <- assay(example_sce[rownames(ref), colnames(ref)]) all.equal(exp(ref$offset), as.numeric(colSums(sub))) # gene parameters: dispersions & sample-specific means head(rowData(ref)) ## ----simData------------------------------------------------------------------ # simulated 10% EE genes sim <- simData(ref, p_dd = diag(6)[1, ], nk = 3, ns = 3, nc = 2e3, ng = 1e3, force = TRUE) # number of cells per sample and subpopulation table(sim$sample_id, sim$cluster_id) ## ----paired-false------------------------------------------------------------- metadata(sim)$ref_sids ## ----paired-true-------------------------------------------------------------- # simulated paired design sim <- simData(ref, paired = TRUE, nk = 3, ns = 3, nc = 2e3, ng = 1e3, force = TRUE) # same set of reference samples for both groups ref_sids <- metadata(sim)$ref_sids all(ref_sids[, 1] == ref_sids[, 2]) ## ----p_dd--------------------------------------------------------------------- # simulate genes from all DD categories sim <- simData(ref, p_dd = c(0.5, rep(0.1, 5)), nc = 2e3, ng = 1e3, force = TRUE) ## ----gi_category-------------------------------------------------------------- gi <- metadata(sim)$gene_info table(gi$category) ## ----densities, echo = FALSE, fig.wide = TRUE, fig.width = 8, fig.height = 3, fig.cap = "Expression densities for an exemplary set of 3 genes per *differential distribution* category. Each density corresponds to one sample, lines are colored by group ID, and panels are split by gene and subpopulation."---- # simulate genes from all DD categories sim <- simData(ref, nc = 2e3, nk = 1, ns = 4, p_dd = c(0.5, rep(0.1, 5)), ng = 1e3, force = TRUE) # normalize sim <- logNormCounts(sim) # get 'n' genes per category n <- 3 gi <- metadata(sim)$gene_info %>% mutate(sim_mean = (sim_mean.A+sim_mean.B)/2) %>% filter(is.na(logFC) | abs(logFC) > 2, sim_mean > 1) gs <- group_by(gi, category) %>% group_modify(~head(.x, n = n)) %>% mutate(id = paste0(gene, cluster_id)) # construct data.frame for ggplot df <- data.frame(t(logcounts(sim)), colData(sim)) %>% melt(id.vars = names(colData(sim))) %>% mutate(id = paste0(variable, cluster_id)) %>% mutate(id = factor(id, levels = gs$id)) %>% filter(id %in% gs$id) %>% mutate(cat = gs$category[match(id, gs$id)]) # use category as facet label labs <- setNames(toupper(df$cat), df$id) labs <- labs[unique(names(labs))] # keep labels only for top row labs_keep <- levels(df$id)[seq(1, length(labs), n)] labs[setdiff(names(labs), labs_keep)] <- "" labs <- as_labeller(labs) # plot expression densities ggplot(df, aes(x = value, col = group_id)) + facet_wrap("id", scales = "free", dir = "v", ncol = 6, labeller = labs) + geom_density() + xlab("expression") + theme_minimal() + theme( axis.text = element_blank(), axis.ticks = element_blank(), panel.spacing = unit(0, "mm"), panel.grid = element_blank()) ## ----rel-lfc, echo = FALSE, fig.wide = TRUE, fig.cap = "t-SNEs of exemplary simulations demonstrating `rel_lfc`'s effect to induce cluster-specific state changes. Cells are colored by cluster ID (top-row) and group ID (bottom-row), respectively. From left to right: No cluster-specific changes, stronger change for `cluster3`, different logFC factors for all clusters with no change for `cluster1`."---- rel_lfc <- list( c(1, 1, 1), # same FC factor for all clusters c(1, 1, 2), # stronger change for cluster3 only c(0, 1, 2)) # cluster-specific logFC factors; no change for cluster1 sim <- lapply(rel_lfc, function(u) simData(ref, rel_lfc = u, nc = (nc <- 1e3), nk = 3, p_dd = c(0.95, 0, 0.05, 0, 0, 0), ng = 1e3, force = TRUE)) # normalize & run dimension reduction sim <- lapply(sim, logNormCounts) sim <- lapply(sim, runTSNE) # arrange plots ps <- lapply(c("cluster_id", "group_id"), function(id) lapply(sim, function(u) { p <- plotTSNE(u, colour_by = id) p$layers[[1]]$aes_params$stroke <- 0 p + guides(fill = guide_legend( override.aes = list(alpha = 1, size = 3))) })) ps <- Reduce("c", ps) lgd <- lapply(ps[c(1, 4)], get_legend) ps <- lapply(ps, "+", theme(legend.position = "none")) plot_grid(nrow = 1, rel_widths = c(8, 1), plot_grid(plotlist = ps, ncol = 3, align = "hv"), plot_grid(plotlist = lgd, ncol = 1)) ## ----p-type, echo = FALSE, fig.wide = TRUE, fig.cap = "t-SNEs of exemplary simulations demonstrating `p_type`'s effect to introduce *type* features. Cells are colored by cluster ID (top-row) and group ID (bottom-row), respectively. The percentage of type features increases from left to right (1, 5, 10%). Simulations are pure EE, i.e., all genes are non-differential across groups."---- sim <- lapply(c(0.01, 0.05, 0.1), function(u) simData(ref, p_type = u, nc = 1e3, nk = 3, ng = 1e3, force = TRUE)) # normalize & run dimension reduction sim <- lapply(sim, logNormCounts) sim <- lapply(sim, runTSNE) # arrange plots # arrange plots ps <- lapply(c("cluster_id", "group_id"), function(id) lapply(sim, function(u) { p <- plotTSNE(u, colour_by = id) p$layers[[1]]$aes_params$stroke <- 0 p + guides(fill = guide_legend( override.aes = list(alpha = 1, size = 3))) })) ps <- Reduce("c", ps) lgd <- lapply(ps[c(1, 4)], get_legend) ps <- lapply(ps, "+", theme(legend.position = "none")) plot_grid(nrow = 1, rel_widths = c(5, 1), plot_grid(plotlist = ps, ncol = 3, align = "hv"), plot_grid(plotlist = lgd, ncol = 1)) ## ----simData-type------------------------------------------------------------- # simulate 5% of type genes; one group only sim <- simData(ref, p_type = 0.1, nc = 2e3, ng = 1e3, force = TRUE, probs = list(NULL, NULL, c(1, 0))) # do log-library size normalization sim <- logNormCounts(sim) ## ----heatmap-type, fig.width = 12, fig.height = 8, fig.cap = "Exemplary heatmap demonstrating the effect of `p_type` to introduce cluster-specific *type* genes. Included are type genes (= rows) with a simulated expression mean > 1, and a random subset of 100 cells (= columns) per cluster; column annotations represent cluster IDs. Bins are colored by expression scaled in row direction, and both genes and cells are hierarchically clustered."---- # extract gene metadata & number of clusters rd <- rowData(sim) nk <- nlevels(sim$cluster_id) # filter for type genes with high expression mean is_type <- rd$class == "type" is_high <- rowMeans(assay(sim, "logcounts")) > 1 gs <- rownames(sim)[is_type & is_high] # sample 100 cells per cluster for plotting cs <- lapply(split(seq_len(ncol(sim)), sim$cluster_id), sample, 100) plotHeatmap(sim[, unlist(cs)], features = gs, center = TRUE, colour_columns_by = "cluster_id", cutree_cols = nk) ## ----phylo-tree, fig.small = TRUE, fig.height = 4, fig.cap = "Exemplary phylogeny. The phylogenetic tree specified via `phylo` relates 3 clusters such that there are 2 main branches, and clusters 1 and 2 should be more similar to one another than cluster 3."---- # specify cluster phylogeny tree <- "(('cluster1':0.4,'cluster2':0.4):0.4,('cluster3': 0.5,('cluster4':0.2,'cluster5':0.2,'cluster6':0.2):0.4):0.4);" # visualize cluster tree library(phylogram) plot(read.dendrogram(text = tree)) ## ----simData-phylo------------------------------------------------------------ # simulate 5% of type genes; one group only sim <- simData(ref, phylo_tree = tree, phylo_pars = c(0.1, 1), nc = 800, ng = 1e3, dd = FALSE, force = TRUE) # do log-library size normalization sim <- logNormCounts(sim) ## ----heatmap-phylo, fig.width = 12, fig.height = 8, fig.cap = "Exemplary heatmap demonstrating the effect of `phylo_tree` to introduce a hierarchical cluster structure. Included are 100 randomly sampled non-state, i.e. type or shared, genes (= rows) with a simulated expression mean > 1, and a random subset of 100 cells (= columns) per cluster; column annotations represent cluster IDs. Bins are colored by expression scaled in row direction, and both genes and cells are hierarchically clustered."---- # extract gene metadata & number of clusters rd <- rowData(sim) nk <- nlevels(sim$cluster_id) # filter for type & shared genes with high expression mean is_type <- rd$class != "state" is_high <- rowMeans(assay(sim, "logcounts")) > 1 gs <- rownames(sim)[is_type & is_high] # sample 100 cells per cluster for plotting cs <- lapply(split(seq_len(ncol(sim)), sim$cluster_id), sample, 50) plotHeatmap(sim[, unlist(cs)], features = gs, center = TRUE, show_rownames = FALSE, colour_columns_by = "cluster_id") ## ----countsimQC, eval = FALSE------------------------------------------------- # # load required packages # library(countsimQC) # library(DESeq2) # # simulate data # sim <- simData(ref, # ng = nrow(ref), # nc = ncol(ref), # dd = FALSE) # # construct 'DESeqDataSet's for both, # # simulated and reference dataset # dds_sim <- DESeqDataSetFromMatrix( # countData = counts(sim), # colData = colData(sim), # design = ~ sample_id) # dds_ref <- DESeqDataSetFromMatrix( # countData = counts(ref), # colData = colData(ref), # design = ~ sample_id) # dds_list <- list(sim = dds_sim, data = dds_ref) # # generate 'countsimQC' report # countsimQCReport( # ddsList = dds_list, # outputFile = ".html", # outputDir = "", # outputFormat = "html_document", # maxNForCorr = 200, # maxNForDisp = 500) ## ----iCOBRA-run-method-wrapper------------------------------------------------ # 'm' is a character string specifying a valid `pbDS` method .run_method <- function(m) { res <- pbDS(pb, method = m, verbose = FALSE) tbl <- resDS(sim, res) left_join(gi, tbl, by = c("gene", "cluster_id")) } ## ----iCOBRA-calc-perf-wrapper------------------------------------------------- # 'x' is a list of result 'data.frame's .calc_perf <- function(x, facet = NULL) { cd <- COBRAData(truth = gi, pval = data.frame(bind_cols(map(x, "p_val"))), padj = data.frame(bind_cols(map(x, "p_adj.loc")))) perf <- calculate_performance(cd, binary_truth = "is_de", maxsplit = 1e6, splv = ifelse(is.null(facet), "none", facet), aspects = c("fdrtpr", "fdrtprcurve", "curve")) } ## ----iCOBRA-comparison, warning = FALSE, message = FALSE, fig.height = 4, fig.width = 9---- # simulation with all DD types sim <- simData(ref, p_dd = c(rep(0.3, 2), rep(0.1, 4)), ng = 1e3, nc = 2e3, ns = 3, force = TRUE) # aggregate to pseudobulks pb <- aggregateData(sim) # extract gene metadata gi <- metadata(sim)$gene_info # add truth column (must be numeric!) gi$is_de <- !gi$category %in% c("ee", "ep") gi$is_de <- as.numeric(gi$is_de) # specify methods for comparison & run them # (must set names for methods to show in visualizations!) names(mids) <- mids <- c("edgeR", "DESeq2", "limma-trend", "limma-voom") res <- lapply(mids, .run_method) # calculate performance measures # and prep. for plotting with 'iCOBRA' library(iCOBRA) perf <- .calc_perf(res, "cluster_id") pd <- prepare_data_for_plot(perf) # plot FDR-TPR curves by cluster plot_fdrtprcurve(pd) + theme(aspect.ratio = 1) + scale_x_continuous(trans = "sqrt") + facet_wrap(~ splitval, nrow = 1) ## ----session-info------------------------------------------------------------- sessionInfo()