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
['d2 dG', 'g2 ea']  
X:1
L:1/8
M:4/4
K:G
 d2 dG BGdB | d2 dG B>def | d2 dG BGdB | A<AeA B>def | d2 dG BGdB | d2 dG B>def | d2 Gd B2 GB | 
 A<AeA B>def || g2 ea e2 d<e | g2 ea Bcde | g2 ea e2 d<e | d2 dG B>def | g2 ea e2 d<e | 
 g2 ea Bcde | g2 ag fefd | efeA B>def ||  