Hello everyone, I have looked in the forum but could not find any information. I want to add labels on cluster in a t-SNE plot. I am using Scater and Scran packages for scRNA-Seq data analysis. I also want to change the color palette but could not achieve it too.

I used +geomlabelrepel(data$clusters) but R crashed with that command.

Thank you in advance.

Text labels can be added via geom_text or annotate, provided you know the coordinates you are interested in. For example, the next version of scater::plotReducedDim provides a text_by= argument that adds an identifying label at the centre of each cluster, which is useful in cases where there are more clusters than unique colours.

library(scater)

## Set up an example SingleCellExperiment
data("sc_example_counts")
data("sc_example_cell_info")
example_sce <- SingleCellExperiment(
    assays = list(counts = sc_example_counts), 
    colData = sc_example_cell_info
)
example_sce <- normalize(example_sce)

## Make labels at any coordinate you wish.     
gg <- plotPCA(example_sce) 
gg + geom_text(aes(label=label), data=data.frame(X=0, Y=0, label="YAY"))

Colours should be changeable by overriding the existing fill.

gg <- plotPCA(example_sce, colour_by="Treatment") 
gg # orange and blue

gg + scale_fill_manual(values=c(treat1="red", treat2="green"))