6.9 years ago by
New York, NY
I think that diagram style is not being used any more (probably deprecated). When I look at the detailed diagram explanations, I saw this particular screenshot that has the dotted edge style:

but when you look at that pathway at its current state, they don't have those styled edges any more:
http://www.reactome.org/PathwayBrowser/#DIAGRAM=109581
So looking at this example, my wild guess is that they represent pathway memberships where you have hiearchical pathways and in them there is an umbrella (top) pathway and it has child pathways to it. In BioPAX these relationships are captured via PathwayComponent
s; for example take a look at the corresponding "Apoptosis" pathway in Pathway Commons:
http://www.pathwaycommons.org/pc2/get?uri=http://purl.org/pc2/4/Pathway_a9eea90b0e56a117e7f908304ab0f6e0
and simply search for Pathway_a9eea90b0e56a117e7f908304ab0f6e0
to look up the "top" Apoptosis pathway. There, you will see four PathwayComponent
s that are included in this pathway -- I believe those dotted edges are meant to capture these types of relationships.
Another possibility is the so called "generic" relationships in BioPAX (like AKT representing AKT1/2/3), but I think they are not being visualized in Reactome Pathway Diagram Viewer, but rather being shown on the panel below when you click on a specific entity.