Just wondering how you determine the range of colors at which you represent your expression data. Is there a standard or is it case-by-case basis (i.e. expecting minute changes between groups, etc)?
library(gplots) # contains heatmap.2
plotgenes <- matrix(rnorm(1000),100,10) # generate random data
colbreak = c(seq(-2,-.5,length=100),seq(-.5,.5,length=100),seq(.5,2,length=100))
mycolors <- colorRampPalette(c("red", "black", "green"))(n = 299)
par(cex.main=.8)
ht <- heatmap.2(plotgenes, main=title, col=mycolors, breaks=colbreak,
density.info="none", trace="none", srtCol = 45, margins=c(7,10), cexCol= .7,
offsetCol = -.6, dendrogram=c("none"), symm=F,symkey=F,symbreaks=T,
scale="row", Colv = NA)