Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/8
M:6/8
K:D
['FAA dAA BAG A2 G FAA DAA']  
X:1
L:1/8
M:6/8
K:D
 FAA dAA | BAG A2 G | FAA DAA | GAG FED | FAA dAA | BAG A2 G | FAA DAA | G2 E FED | dBA A z a | 
 agf g3 | fdA F2 A | G3 FED | dBA A z a | agf gag | fdA F2 A | G2 E FED |]  