Originally Posted by: equatorTechnically it is not the same scale, they are two different scales.
The F Ionian(F-G-A-Bb-C-D-E-F) is a major scale, and is supposed to be played over an F major Chord.
The G Dorian Mode(G-A-Bb-C-D-E-F-G) is a minor scale with a major sixth instead of a minor sixth; and it is supposed to be played over a G minor chord.
This, by the way, is part of the reasoning behind my disagreeing with you on the usefulness of relative scales over a blues backing.