Chemical and physical agents assayed in tests for mitotic intergenic and intragenic recombination in Aspergillus nidulans diploid strains.

Data from Aspergillus nidulans mitotic recombination assays published over the period 1960-1986 are briefly reviewed. The results of the testing of 104 chemical agents and three physical agents are summarized. A tentative comparison of the performance of recombinational, mutational and aneuploidy assays in A. nidulans suggests that the former can effectively detect DNA-damaging agents which either induce true genetic recombination (intergenic or intragenic crossing-over) or mimic it by inducing chromosome structural damage which allows the expression of recessive genetic markers. On the other hand, aneuploidy tests proved to be sensitive both to chemicals directly affecting chromosome segregation (e.g. spindle poisons) and to the majority of DNA-reactive compounds assayed.