Craft a composition that integrates the assigned alphabet-related musical pattern and the provided melodic theme.
X:1
L:1/8
M:2/4
K:G
['GABc B2 AB cAGF G2']  
X:1
L:1/8
M:2/4
K:G
 D | GABc | B2 AB | cAGF | G2 z D | GABc | B2 AB | cAGF | G2 z B | dcBd | d2 cB | cdec | c2 BD | 
 GABc | B2 AB | cAGF | G2 z |]  