Watch the She's Dominant Two online guitar lesson by Matthieu Brandt from 50 Jump Blues Licks You MUST Know
One of the more common chord substitutions in a 12 bar jump blues progression is changing the V to IV to I progression in bars 9 to 11 to a II - V- I progression. Most jump blues progressions are played in a major key, which means that the II chord is mostly a minor or minor seventh chord. This lick goes another step further, we're changing the II minor chord to a dominant seventh chord. Which makes for a chain of dominant seventh chords; II-V-I.