Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/8=220
M:4/4
K:G
['DG (3GGG ABde fdde fdcA DGFG A2']  
X:1
L:1/8
Q:1/8=220
M:4/4
K:G
|: DG (3GGG ABde | fdde fdcA | DGFG A2 de |1 fdcA GBAF :|  