More about Venn Diagrams...

Package ‘VennDiagram’
     This will draw a Venn Diagram if you know the numbers you want to put into each part of the diagram. It makes nice Venn Diagrams.

Venn Diagrams with the Package 'gplots'
    This will calculate a Venn Diagram from lists. For a simple two list comparison, it's not really necessary.

These functions for comparing lists are sufficient:

• intersect()  
• setdiff(listMCP, listJPR) # in 1st list NOT 2nd
• unique(c(listMCP,listJPR)) # combined list of both