5X volume of binding buffer (20 mM HEPES pH 7.9, 20 mM KCl, 1 mM CaCl2, 1 mM MnCl2) was added to the samples and the pH adjusted with sodium acetate before being transferred to a purification column (ActiveMotif, 58002) and centrifuged at 11,000 xg for 30 sec. The column was then washed with 750 µl wash buffer and dried by centrifugation for 2 min. DNA was eluted with 25 µl elution buffer and the DNA concentration measured with a Qubit 3.0 Fluorometer (Life Technologies). As described in detail at: doi: 10.1002/0471142727.mb2129s109