--- a
+++ b/R/DIscBIO-generic-PCAplotSymbols.R
@@ -0,0 +1,57 @@
+#' @title Plot PCA symbols
+#' @description Generates a plot of grouped PCA components
+#' @param object \code{DISCBIO} class object.
+#' @param types If types=NULL then the names of the cells will be grouped
+#'   automatically. Default is NULL
+#' @importFrom grDevices rainbow
+#' @importFrom graphics legend
+#' @return Plot of the Principal Components
+#'
+setGeneric("PCAplotSymbols", function(object, types = NULL) {
+  standardGeneric("PCAplotSymbols")
+})
+
+#' @export
+#' @rdname PCAplotSymbols
+setMethod(
+  "PCAplotSymbols",
+  signature = "DISCBIO",
+  definition = function(object, types = NULL) {
+    if (length(object@MBclusters) == 0) {
+      stop("run Exprmclust before PCAplotSymbols")
+    }
+    total <- object@MBclusters
+    types <- names(object@fdata)
+    types <- gsub("_[0-9]+", "", types)
+    coloc <- rainbow(length(unique(types)))
+    total <- object@MBclusters$pcareduceres
+    syms <- vector()
+    plot(
+      total[, 1],
+      total[, 2],
+      xlab = "PC1",
+      ylab = "PC2",
+      pch = 20,
+      cex = 0,
+      col = "grey",
+      las = 1
+    )
+    for (i in seq_len(length(unique(types)))) {
+      f <- types == sort(unique(types))[i]
+      syms <- append(syms, ((i - 1) %% 25) + 1)
+      points(
+        total[f, 1],
+        total[f, 2],
+        col = coloc[i],
+        pch = ((i - 1) %% 25) + 1,
+        cex = 1
+      )
+    }
+    legend(
+      "topright",
+      legend = sort(unique(types)),
+      col = coloc,
+      pch = syms
+    )
+  }
+)