String DB

RAS, RAF, MEK, MAPK... or something like that. That's what I remember as being the chain of gene activation to activate an oncogene leading to cancer (P53 getting its ass kicked) . No I can't remember the details but these activation/interactions form a tree of what gene up or downregulates the function of another and it's quite a complicated part of genetics and bioinformatics. But I found a website recently that I hadn't seen before and thought of sharing it because apart from getting a nice little description of what the gene does in different species, it has nice spider diagrams like this showing gene relationships:

http://string-db.org/
A search example, PAX6: http://string-db.org/newstring_cgi/show_network_section.pl?caller_identity=expasy_api&identifier=pax6
If you click continue at the bottom of that page you see the diagram.