R中的粗体希腊字母

Question

I want to add a greek letter to my the margin of a figure, and I used the line of code below:

mtext(side=2,line=6,text=expression(paste(beta,"-Actin Normalized")),font=2,cex=2)

However, when I use the mtext function in combination with greek letters it no longer bolds the line of text. Is there any good way to add margin text with greek letters and retain bold font?

Thanks.

Answer 1

You can use the bold plotmath function:

expression(bold(paste(beta,"-Actin Normalized")))

And before you ask for bold(beta) you should read this information from Prof Ripley on Rhelp