So G major, for example has a key signature of one sharp, but this is also the key signature for E minor. To find this ... and raise the seventh note of the scale. For example, in A harmonic ...
The A Ionian mode (that's the same as the A major scale, remember ... you that the chords are Bm (hence ii is lowercse), E and A in the key of A major. Finally, here's a simple Ionian solo.