I would like to do a "relatedness" (a tree diagram) analysis based on RNA-seq or microarray expression levels (Exp. A B C) with different cell lines (A, B and C).

Gene ID     Exp.-A      Exp.-B      Exp.-C
Gene A         40          50         20
Gene B         100         90         30
Gene C         20          30         90

So eyeballing I can see that cell line A and B are more related in their expression levels than is C but I would like to not eyeball.

1.) What software would tell me this in some kind of numeric "cladogramatic" way?

2.) I use R here and there so what would be a good approach with R?