The Dorian scale is the same as the Mixolydian scale except that the third note is flattened by a semitone. To convert a Mixolydian to a Dorian key signature, add a flat to, or remove a sharp from, it. Likewise, to convert a Dorian to a Mixolydian key signature, remove a flat from, or add a sharp to, it.
To convert a Dorian to an Ionian key signature add 2 sharps to, or remove 2 flats from, it. Likewise, to convert an Ionian key signature to a Dorian key signature, add 2 flats to, or remove 2 sharps from, it.
Below you will find a sample of tunes in the Dorian scale.