Amplified yeast genomic DNA was diluted to 30 µl of 0.1 M PBS pH 7.4 (P5493, Sigma) (6.54 µg DNA in 30 µl PBS, 60 nmol of DNA). MMC was dissolved in 0.1 M PBS, pH 7.4, to prepare a 100 mM stock solution. 0.24 µmol of mitomycin C (2.4 µl of 0.1 M MMC stock solution was diluted to 27 µl in 0.1 M PBS) and 12 µmol of Na2S2O4 (3 µl of 40 mM Na2S2O4 in water) were added to amplified yeast genomic DNA and incubated in a PCR tube in a thermoshaker at 40 °C, 400 rpm with open lid in fume hood. MMC-treated DNA was purified by using 1.8x Ampure XP beads and eluted in 20 µl 10 mM Tris-HCl, pH 8.0.                