DELETION MAPPING OF THE NIIA-NIAD GENE REGION OF ASPERGILLUS-NIDULANS

The genetic fine-structure of the niiA niaD gene region of Aspergillus nidulans has been studied using deletion mapping. Deletions were identified as niiA niaD double mutants and comprised 1% of spontaneous chlorate-resistant mutants. All such double mutants were shown to involve deletions and their frequency was not increased by mutagenic treatment with either N-methyl-N′-nitro-N-nitrosoguanidine or with ultraviolet light. Deletion maps of the niaD and niiA genes have been constructed. A further class of mutation was also mapped using the deletions. These crn mutations, which affect a gene whose function is as yet unknown, map on the centromere proximal side of niiA. This analysis of a eukaryote gene cluster will provide a framework upon which to base studies of the regulation of the nitrate assimilation pathway. © 1979, Cambridge University Press. All rights reserved.