Patent ID: 7824900

Claim:
A DNA analyzing apparatus comprising: a bath containing an electrophoresis medium; a first electrode and a second electrode arranged in the bath opposite each other in a width direction of the bath; a light sensing device located in the bath at a height different from the heights of the first and second electrodes and at a position between the first electrode and the second electrode in the width direction of the bath; a plurality of probe electrodes arranged along the width direction of the bath and above a surface of the light sensing device; a plurality of different spots arranged on the probe electrodes, each of the spots including probe DNA fragments having known base sequences; and a voltage control circuit which controls voltages applied to the first electrode, the second electrode, and the plurality of probe electrodes; wherein the plurality of probe electrodes are divided into plural sets of the probe electrodes, each of the sets of the probe electrodes comprising a number of probe electrodes that are adjacent to each other along the width direction of the bath, wherein the probe DNA fragments that are close to the second electrode have a smaller number of bases than the probe DNA fragments that are close to the first electrode, the number of bases in one of the probe DNA fragments on one of the probe electrodes that is closest to the first electrode is the largest among the probe DNA fragments that are close to the first electrode, and the number of bases in one of the probe DNA fragments on another of the probe electrodes that is closest to the second electrode is the smallest among the probe DNA fragments that are close to the second electrode; and wherein, when the potential of the first electrode is lower than the potential of the second electrode, a plurality of types of sample DNA fragments injected in the electrophoresis medium migrates from the first electrode towards the second electrode in the electrophoresis medium, and, after a predetermined time, a sample DNA fragment having a predetermined number of bases among the sample DNA fragments reaches a location of the electrophoresis medium directly above one of the probe electrodes and the voltage control circuit sets an equal voltage in the first electrode, the second electrode, and the plurality of the probe electrodes, and each of the probe DNA fragments on the one of the probe electrodes and the sample DNA fragment are complementary each other and have almost identical number of bases.