[R] plot question

[Tiandao Li]

Hello,

I have a question about how to plot a series of data. The folloqing is my 
data matrix of n
> n
             25p    5p  2.5p 0.5p
16B-E06.g 45379  4383  5123   45
16B-E06.g 45138  4028  6249   52
16B-E06.g 48457  4267  5470   54
16B-E06.g 47740  4676  6769   48
37B-B02.g 42860  6152 19276   72
35B-A02.g 48325 12863 38274  143
35B-A02.g 48410 12806 39013  175
35B-A02.g 48417  9057 40923  176
35B-A02.g 51403 13865 43338  161
45B-C12.g 50939  3656  5783   43
45B-C12.g 52356  5524  6041   55
45B-C12.g 49338  5141  5266   41
45B-C12.g 51567  3915  5677   43
35A-G04.g 40365  5513  6971   32
35B-D01.g 54217 12607 13067   93
35B-D01.g 55283 11441 14964  101
35B-D01.g 55041  9626 14928   94
35B-D01.g 54058  9465 14912   88
35B-A04.g 42745 12080 34271  105
35B-A04.g 41055 12423 34874  126

colnames(n) is concentrations, rownames(n) is gene IDs, and the rest is 
Intensity. I want to plot the data this way.
x-axis is colnames(n) in the order of 0.5p, 2.5p,5p,and 25p.
y-axis is Intensity
Inside of plot is the points of intensity over 4 concentrations, points 
from different genes have different color or shape. A regression line of 
each genes crosss different concetrations, and at the end of line is gene 
IDs.

Thanks,

Tiandao