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
['=fdcB A=FFF D=FFF dFcF', 'fdef g2 bg dgbg agfd ggga bggg']  
X:1
L:1/8
M:4/4
K:G
 DGBd g3 e | =fdcB A=FFF | D=FFF dFcF | BGAF DGGG | DGBd ggge | =fdcB A=FFF | D=FFF dFcF |1 
 BGAF DGGG :|2 BGAF DGBd |: g2 bg dgbg | fgag fdef | g2 bg dgbg | agfd ggga | bggg agfd | 
 gbag fdcA | DGBd gbag |1 fdcA BGBd :|2 fdcA BGGG ||  