How to change color of the points and remove the joined line in the given code?

I use this code

{data1, data2} = Transpose[Table[{2 n, 3 n + 100}, {n, 20}]]; a = ListPlot[{data1, data2}, Joined -> True,    PlotStyle -> {Directive[Red, Thickness[Scaled[10^-2]]],      Directive[Blue, Thickness[Scaled[10^-2]]]}, Mesh -> All,    MeshStyle -> Directive[PointSize[Large], Red],   ClippingStyle -> False] 

and I get this picture

enter image description here

Now, I have two questions:

  1. How can I ask Mathematica to change the color (red to blue) and shape (circle to diamond) of the plotmarker in the upper curve?
  2. How can I remove the joined line for the upper curve?