Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/4
M:4/4
K:G
['F/G/ A', 'A A']  
X:1
L:1/4
M:4/4
K:G
|: D G G F/G/ | A E E2 | F/G/ A A/B/ A | B G G3/2 E/ | D G G F/G/ | A E E2 | F/G/ A D E/F/ | 
 G G G2 :: A A B2 | A A F2 | G G E/F/ G | A A F/G/ A | A A B2 | A A F2 | G G E/G/F/E/ | D F D2 :|  