Attempts to produce Genetical Changes in Drosophila by Centrifugation

STUBBE 1 was the first to observe an increase in the mutational frequency in Antirrhinum by subjecting chemically treated seeds and seedlings to centrifugation. Irrespective of the chemical used, he always found approximately the same increase in mutation rate over the non-centrifuged controls. Additional evidence in plant material was obtained by Kostoff 2–4 , who found that mechanical stress applied in the form of ‘pseudogravity’ created by centrifugation resulted in the appearance of chromosomal fragments and other structural changes. Contrary to these findings, Sax 5 , working on Tradescantia , observed an increased frequency of chromosomes and chromatid interchanges only when centrifugation was applied during X -radiation.