Overlaying two graphs using ggplot2 in R

Question

I have two graphs and I am trying to overlay one on top of the other:

An example of the data frame \"ge\" looks like this. In actuality there are 10 Genes with 200

Answer 1

One way is to add the geom_line command for the second plot to the first plot. You need to tell ggplot that this geom is based on a different data set:

ggplot(avg, aes(x=Gene, y=mean)) + 
  geom_point() + 
  geom_line() + 
  geom_errorbar(aes(ymin=mean-sd, ymax=mean+sd), width=.1) +
  geom_line(data = ge, aes(x=Gene, y=Exp, group=Sample, colour="#000099"),
            show_guide = FALSE)

The last geom_line command is for creating the lines based on the raw data.