How to italicize just gene names in my heatmap (using R)?

Question

I am doing a heatmap in R (gplots) and I would like to italicize just my gene names (in my example - gene1, gene2 and gene3). For example:

df <- data.frame(Gene = c ("gene1", "gene2",  "gene3"), value = c(3, 2, 2.5), time = c("10d","10d","10d"))
gplots::heatmap.2(cbind(df$value, df$value), trace= "none", Colv = NA, labCol = "", labRow = df$Gene, Rowv=FALSE)

I tried (did not work):

df <- data.frame(Gene = c ( expression(italic("gene1", "gene2",  "gene3"))), value = c(3, 2, 2.5), time = c("10d","10d","10d"))

or

df <- data.frame(Gene = expression(italic(c ("gene1", "gene2",  "gene3"))), value = c(3, 2, 2.5), time = c("10d","10d","10d"))

Any suggestions?

Answer 1

This will do it progammatically:

gene_list <- as.character(df$Gene)

make_italics <- function(x) {
  as.expression(lapply(x, function(y) bquote(italic(.(y)))))
}

heatmap.2(
  cbind(df$value, df$value),
  trace = "none",
  Colv = NA,
  labCol = "",
  labRow = make_italics(gene_list),
  Rowv = FALSE
)