Abstract: Arranging a pair of temperature control units on both sides of gel 1 and arranging light-transmitting slit 134 on one of the elements, irradiation of an excitation beam over the gel 1 and signal detection are practiced through the slit 134. Introducing dry air onto the slit part, mildew occurrence is prevented on the detecting part. Detecting the power level applied to the gel and calculating the temperature of the temperature control units so that the gel temperature might be a predetermined temperature, on the basis of the detected power level, thereafter carrying out the feedback control of the power level, the gel temperature can be controlled appropriately and strictly during electrophoresis in an automatic fluorescent electrophoresis system, so that high-speed analysis can be done highly reproducibly at a higher voltage applied even by SSCP.

Abstract: The improved DNA base sequencer comprising an electrophoresis plate having a gel electrolyte layer held between two glass plates, one of which is partially cut away on the top edge in the direction of width, an assay compartment for accommodating said electrophoresis plate in a vertically erect position, a lower reservoir of a buffer solution in which the lower part of the gel electrolyte layer in the electrophoresis plate is to be immersed, an upper reservoir of a buffer solution in which the upper part of said electrolyte layer is to be immersed, photoexciting laser light applying means by which laser light is emitted from a lateral side of the electrophoresis plate in such a way that it crosses the lanes in said plate at right angles, and fluorescence detecting means by which the fluorescence emitted from a DNA fragment illuminated with the laser light is picked up and converted to an electric signal, and the apparatus is characterized in that a sharkstoothcomb made of a water-swellable material is inserte