A recent posting by Drathmere at 40k Hobby Blog started me thinking about where the modern traitor chapters emerge from. From codex: space marines, we know the "more than one-half" of all marine chapters derive from Guilliman's gene-seed. Therefore, it may follow (but perhaps not necessarily) that the bulk of modern traitor chapters derive from the Ultramarines.
So my thought for the day is this: could it be that Guilliman's gene-seed has ultimately created more traitor marines than the Iron Warriors (etc.)? Or, as my suggestive image may indicate, do modern traitors gene-seed mostly come from elsewhere :)
(Image: Dark Angels Ezekiel -- in traitor form!).