Here’s an easy way to use the rich contour of the melodic minor scale to organize melodic material into 4ths moving from dominant to tonic. Take a look at the example above.
In the first measure I create two four-note shapes based upon the diatonic 4ths found in both a C major scale, and in a D melodic minor scale. You’ll notice there is no C# in this measure (the 7th degree of the D melodic minor scale, which is a strongly “defining” note). But the first note in the 2nd measure is a Db, which both sonically and functionally implies the D melodic minor. It also is the first note of a new scale, Ab melodic minor. (So the Db functions as a common “pivot” tone between both scales.)
Of course it is the Ab melodic minor that is rich in altered harmonic tensions over the G7 chord (specifically, -5/#11, +9, -13, -9). Yet this scale is organized into 4ths, as well, in order to continue the general shape and direction of the melodic line. Again, there is a common “pivot” note in measure 3 (the B natural, which also functions enharmonically as Cb, the third of the Ab melodic minor scale).
In the 3rd measure the shape changes slightly, with a descending version of the C maj7 chord. Then the 4ths emerge again (with a little variation between the F# and G) until the end. The general color of the line is a bit on the “modern” side because of the 4ths, but has enough familiar harmonic elements in it so that it can function quite well in a bebop or post bop context.
If you’d like to explore the vast array of harmonic possibilities by applying melodic minor scales combinations over ii-V7-I, please consider my e-book, Melodic Minor Scale Jazz Studies: Tonal Organizations and Applications Over Dominant 7th Chords. Click the link below for a free, downloadable pdf of this etude: