Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/8
M:4/4
K:G
['', 'DGGA BGAG', 'Ad (3ddd edcA']  
X:1
L:1/8
M:4/4
K:G
 D |: DGGA BGAG | FDDE FDDC | DGGA BGAG | AdcA AG G z :| Ad (3ddd edcA | ABcB AGFD | 
 Ad (3ddd edcA | ABcA AGGG | Ad (3ddd edcA | ABcB AGFD | dBcA BGAG | AdcA AG G z |]  