Tetrad Analysis

Abstract

There are several makes of micromanipulators available commercially, all of which can be used for dissection of yeast asci and isolation of the ascospores. Most of these are designed as free-standing instruments, but in at least one, the needle-holder and adjusting screws, both for the operation of the needle itself and for moving the dissecting chamber, are mounted on the microscope stage itself. One of the earliest commercial instruments produced was the de Fonbrune micromanipulator, in which the controls were combined into one “joystick” arrangement, which operated a set of hydraulic plungers con­nected by flexible lines to aneroid capsules in the needle holder. In other in­struments, the movement is purely mechanical. Those instruments which are designed for microinjection of animal cells and plant protoplasts, and which are capable of rather slow, but very precise movements, can be used for dis­section of yeast asci, but are possibly less easy to manipulate than those in­struments specifically designed for the isolation of yeast ascospores.