A rapid autoradiographic technique for chromosomal squash preparations

A rapid method of autoradiography for squash preparations of Drosophila larval polytene chromosomes has been described. The method utilizes treatment of the preparation with scintillation cocktail, Omnifluor-toluene mixtures, prior to developing the autoradiograms. The autoradiograms can be obtained with near maximum efficiency within 72 hr. The suggested optimum time of exposure and pre-treatment is 24 hr. dry exposure plus 48 hr. in the fluid. The percentage of 3H-uridine labelled cells by this method appears to be about 86 to 92% as compared to about 95% by conventional method of 14 to 16 days dry exposure. The resolution seems to be better, and location of grains appears to be undisturbed. (author)