Genetic analyses method development, experimental

In the method of delayed coincidences, the coincidence counting rate between detectors responding selectively to genetically related particles, e.g., a jS- or a-par-ticle and a y-ray or an electron or between y-rays, is plotted as a function of a time delay inserted in the electronic circuits used to detect one of them. The development of this method and of improved electronic techniques has led to the use of resolution times of between 10" and 10 sec. We shall not discuss these methods here, for they have been very adequately reported by Bell [i9], 2ff]. Further analysis of the experimental data has made it possible to measure lifetimes of the order of 10 sec. The limit to the method seems to be determined by the scintillating properties of the phosphor and its physical size. 

It appears that plant lipid metabolism may be amenable to experimental manipulation by the isolation of a wide spectrum of mutants. We anticipate that the mutants described here will provide useful tools for studies of the regulation and functional significance of lipid unsaturation. The anticipated development of more advanced methods of genetic analysis in Arabidopsis (Estelle and Somerville, 1986) may also facilitate the isolation of the genes which complement these mutations. 

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