Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/8
M:2/2
K:G
['G8 |{D} A8', 'B>c dcBA B2 z2 G8 |{D} A8']  
X:1
L:1/8
M:2/2
K:G
{D} G8 |{D} A8 |{D} BABc d2 GB | c>dB>c A>BG>B | AGFE D>EF>E |{D} G8 |{D} A8 | B>AB>c d>ef>g | 
 c>BA>G B>AG>F | G2 B2 G2 :: Bc | d2 Bc d2 B>d | e>dc>B c2 A>B | c2 A>B c2 B>c | dcBA B2 z2 | 
{D} G8 |{D} A8 | B>AB>c d>ef>g | c>BA>G B>AG>F | G2 B2 G2 :|  