Overall gene arrangements of MAT loci, APN1, and SLA2 in the species A. fumigatus, N. fischeri, and E. nidulans. In A. fumigatus, each isolate has either a MAT-1 (encoding a MAT protein with an alpha domain) or a MAT-2 (encoding a MAT protein with an HMG domain) idiomorph located between a single genome copy each of APN1 and SLA2. In N. fischeri, MAT1 is located between APN1 and SLA2, whereas MAT2 is located between the dAPN1 and dSLA2 pseudogenes. In E. nidulans, MAT1 and MAT2 are located on different chromosomes, bordered by only one of SLA2 and APN1, respectively. Chrom., chromosome.