Plasticware . All experiments were performed in lockable sterilized polypropylene test tubes (capacity of 0.2 to 50 ml). Liquids were transferred by automatic pipettors (Gilson) using sterilized pipette-tips. For volumes larger than 1 ml, sterilized graduated plastic pipettes were used. All tubes were sterilized by steam autoclaving (45min, 121psy176 C).
Centrifuges . Centrifugations were run in cooled or unrefrigerated microcentrifuges (Eppendorf tubes) and refrigerated tabletop centrifuges.
Refrigeration . A refrigerator, a -20psy176 C freezer and a -70psy176 C freezer were used. A refrigerated cabinet (4psy176 C) was used for microcentrifugation and ligation. Liquid nitrogen and crashed ice was also necessary for this study.
Light measurement . A UV/Vis spectrophotometer was used for DNA quantification. An ultraviolet (UV) transilluminating light source (302 nm) was necessary to visualize reaction products. A dark room equipped with a Polaroid camera and a developing unit was used for documentation and for sequencing gel procedures.
Electrophoresis systems. Two power supplies and three different gel-systems (vertical sequencing unit, submerged minigels and horizontal polyacrylamide cleangels) were used together with the necessary auxiliary equipment.
Common laboratory equipment. A pH meter, hotplate-stirrer, vortex mixer, balances for weighting reagents, laboratory timers and desiccators were required. All PCR steps were performed in a laminar flow .