A system for automated DNA electrophoresis, molecular hybridization and electronic detection: II. Electronic...

We have designed and constructed an automated, computer-controlled, nucleic acid hybridization analysis system (Electrophoresis 1987, 8, 255-261). The system performs 9 simultaneous experiments, beginning with submarine electrophoretic separation of the restriction fragments and including microwave fixation of the separated fragments, denaturation, neutralization, prehybridization, hybridization, washing and drying. The final step is electronic detection of the hybridization pattern. The detector system consists of 90 Geiger-Mueller detectors arranged to simultaneously sample the 9 hybridizations at 10 positions each. The hybridization matrix is moved across the detectors by a robot arm in increments preprogrammed by the operator and the entire length of the matrix can be counted. The results are printed out as a plot of radioactive counts vs. distance from the origin of electrophoresis. We describe here the characteristics of the detection system.