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:G
['F/G/ A2 G2 z FAd fed']  
X:1
L:1/8
M:6/8
K:G
 G |"G" G2 g f2 e | d^cd edB |"G" G2 B c2 ^c |"D" d3- dAB | c2 d c2 d |"D" cAF DFA |1 
"D" ded"D7" cdc |"G" B3- B2 :|2"D7" ded cBA |"G" G3- G2 |:[K:D] F/G/ |"D" A2 z"A" G2 z | 
"D" FAd fed |"A" c2 e B2 c |"E7" BA^G"A" A2 F/G/ |"D" A2 z"A" G2 z |"D" FAd fed |"A7" cBA gfe |1 
"D" d3- d2 :|2"D" d3"D7" =cBA ||  