Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
Q:3/8=100
M:6/8
K:D
['G in A FED AGF BAG A2', 'd def Bcd ecA B3 d3 ABA']  
X:1
L:1/8
Q:3/8=100
M:6/8
K:D
"^Key G in ms" A | FED AGF | BAG A2 A | dcd Bcd | ecA d2 ::"^*" d | def Bcd | ecA B3 | d3 ABA | 
 AGF (GE)F | G3 F3 | A2 F<D G2 | B2 G<E F2 | A3 GFE | Ddc d2 :|  