give different shapes to object in scatter plot

Question

I have a basic question with ggplot I have a dataframe with a column merged from another df. there are about 10000 rows:

mytab
              FC1         ID            FC2
1    0.3379713197        ff            0.3392757588
2   -0.8787452838        gg           -0.8746986951
3    0.5918856725        Gm            0.5994792851
4   -0.0180385364        xx           -0.0261098608
5    0.1258282187        ii            0.1358723158

basically I need to do a scatter plot which in X there is FC1, in Y FC2. I do this:

mytab$up <- NA
mytab$up[mytab$FC1>=0] <- "red"
mytab$up[mytab$FC2>=0] <- "darkred"

mytab$down <- NA
    mytab$down[mytab$FC1<=0] <- "lightblue"
    mytab$down[mytab$FC2<=0] <- "blue"

Values are similar so if I colour them, they overlaps so I can't see the position of IDs on scatter plot. my idea is to give a different shape to values to be able to distinguish them. I don't know if it is the right way so I will appreciate your help.