Ionian/Mixolydian Gapped Scales and Hybrids

The Mixolydian scale is the same as the Ionian scale except that its seventh note is flattened by a semitone. To convert an Ionian to a Mixolydian key signature add a flat to, or remove a sharp from, it. Likewise, to convert a Mixolydian to an Ionian key signature, remove a flat from, or add a sharp to, it. Many Celtic, Anglo-American and English folk melodies are Ionian/Mixolydian hybrids. There may be a seventh that is sometimes flattened and sometimes not. Or the tune may be hexatonic, with no seventh at all.

Here are some examples of Ionian/Mixolydian gapped scales and hybrids.