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
['D>GB>G B>c B2 D>GB>G A2 (3GFE D>G', 'G2 g>fe>f']  
X:1
L:1/8
M:4/4
K:G
|: D>GB>G B>c B2 | D>GB>G A2 (3GFE | D>G B2 B>G (3ABc | d>ed>B (3ABA G2 :| g>fe>f g>e d2 | 
 g>fe>g d>B A2 | g2 (3def g>ed>G | d>ed>B A2 G2 | g>fe>f g>ed>G | g>e (3def g2 a2 | 
 b>ga>f g>d (3efg | d>e (3dBG (3ABA (3GFE ||  