A chromosome assay method for the detection of heterokaryon incompatibility (het) genes operating between members of different heterokaryon compatibility (h-c) groups in Aspergillus nidulans

Abstract

Protoplast fusion has made possible the isolation of a diploid strain from haploid parents belonging to heterokaryon compatibility (h-c) groups Q and G1 of Aspergillus nidulans. This diploid was not fully heterozygous as part, or all, of linkage group VI had achieved homozygosity. Heterokaryon compatibility tests conducted between selected pairs of parasexually derived progeny strains facilitated a chromosome assay method for the detection of heterokaryon incompatibility (het) genes. Despite the lack of segregation for the linkage group VI marker, it proved possible to locate het genes on linkage groups III, V, VI and VII. Backcross data detected five het gene differences operating between the h-cQ and h-cG1 parental strains. Two het loci were located on linkage group III.