ReactomePA package I have visualised the enrichment results by means of the
enrichMap function (for an example see the original publication, Figure 1 http://pubs.rsc.org/en/content/articlepdf/2016/mb/c5mb00663e).
I am wondering though what the connections between the nodes mean? When does a connection arise? When there is (sufficient) overlap between the gene sets of the pathway or do the connections come from Reactome database?
Thank you for your help/answers!