Many players are introduced to modes by their connection with the major scale. Not to ignore the introduction, let's make the connection and then cut the umbilical cord so that we understand how the intervals were conceived.
Let's use the C Major scale for the example. The Mixolydian mode is commonly referred to as the fifth mode of the major scale. It is also referred to as the dominant mode. Why? In C Major, the G note is the fifth interval (AKA the dominant note). So the C Major scale consists of C-D-E-F-G-A-B. To create the intervals for the Mixolydian mode we need to match the notes it's coming from before we can release it on it's own (create it's DNA so to speak) Starting from the Majors fifth interval we get G, so we create a G Major scale, G-A-B-C-D-E-F#. We're 1/2 step off (sharp) from the match, but that's the DNA for the Major scale. So to make the match the Mixolydian is going to have to step in and lose 1/2 of a finger for it's DNA card and then it's free to go. Reviewing the DNA between the Major scale and the Mixolydian mode is the Mixolydian had flatten it's 7th interval by 1/2 step to receive it's identity in the Major's. Forget the notes, the Mixolydian modes DNA is 1(root)-2-3-4-5-6-b7 and it's Major. All that for 1/2 step? It almost sounds exactly like the Major scale from the same root note. Yes, but when it's used over a dominant chord progression, ie; A7.........etc.. It stands alone. More of Mixolydian's talents next post.
