To each soil tube, 700 ml of Chelex
buffer (200 mM Tris pH ¼ 8.6, 5.5 % Chelex 100 (Bio-Rad Laboratories),
1 % Triton X-100) was added. Tubes were vortexed
briefly, heated to 94e97 C for 12 min, vortexed for 30 s, then
frozen. Crude DNA solutions were cleaned using glass fiber
filters in a method similar to that described in