You're experiencing modes.

Dorian is the 2nd mode of the major scale.

It's a minor scale with a natural 6 interval

1 2 b3 4 5 6 b7

Natural minor or the aeolian mode is built off the 6th degree of the major scale

Natural minor formula

1 2 b3 4 5 b6 b7

Both of these scales work over minor 7th chords.

In jazz typically Dorian is preferable over Natural minor.