MseI and EcoRI
primers with two additional selective nucleotide bases were used in this step of amplification. Selective amplification was
done using 5 mL of the diluted pre-selective amplification as DNA template in reactions with 10 PCR buffer, 2 mM dNTPs,
25 mMMg2þ, 20mMprimer and 1 U Taq DNA polymerase in a total volume of 20 mL. The selective amplificationwas using 36
cycles including a touch-down programme: a reduction of the annealing temperature from 65 C (scaledown of 0.7 C per
cycle). The final selective amplification products were loaded onto a 6% polyacrylamide gel containing urea and electrophoresed
at 100Wrunning for 2.5 h in 1 TBE buffer, and then visualized using the silver-nitrate staining protocol according
to