Fill-in 

 condition
        
        10¡Ñfill-in buffer                 3(£gL)
        20mM  DTT                     1.5
        0.5mM  dNTP                     3
        50£gg/mL  BSA               1.5
        DNA                                  18
        H2O                                    2
        total                                   29

  method
     1¢X  solution(29£gL)  ¡÷  37¢XC  water bath 5min
        2¢X  room temp. 5 min
        3¢X  add 1£gL enzyme (Klenow:large fragement of E. coli polymerase I)
        4¢X  room temp. 30 min