The TX; Y test for the detection of nondisjunction and chromosome breakage in Drosophila melanogaster. I. Analysis of spontaneous events and results of male exposure.

The translocation X; Y test is a selective system in Drosophila melanogaster designed to detect and distinguish among sex chromosome nondisjunction, chromosome breakage, and X-Y interchange. In the test, only exceptional progeny survive. This enables the investigator to score thousands of progeny with relative ease. The distribution of spontaneous events occurring in individual TX; Y males are analyzed in this paper. Evidence is obtained suggesting that the clusters of two products arising from a single nondisjunction can significantly affect the distribution of recovered chromosome gain or chromosome loss events. Non-parametric statistical methods are therefore recommended for the analysis of TX; Y data. In addition, use of the TX; Y test following exposures of pre-adult males to X-rays, heat shock, cold shock, colchicine, dimethyl sulfoxide (DMSO), and trifluralin are presented. Significant increases in nondisjunction (both gain and loss) were obtained following exposures to heat shock, cold shock, DMSO and trifluralin. Significant increases in chromosome breakage and X-Y interchange were obtained after exposures to X-rays and heat shock. These results indicate that the TX; Y test is an efficient method for detecting aneuploidy. Further work is needed, however, to fully validate this system for the routine screening of aneuploidy-inducing agents.