Fig. 1. Schematic representation of the mating-type region that is located on the right arm of chromosome II in S. pombe. The mating-type region consists of three linked loci; mat1 (checkered/black box), mat2-P (checkered box) and mat3-M (black box). mat2/3 is surrounded by two inverted repeats, IR-L and IR-R, with perfect sequence identity (block arrows). In the K-region separating mat2-P and mat3-M there is a 4.3 kb sequence, denoted cenH, with 96% homology to the repeats at cen2 (white box). The inserted ade6⁺ reporter gene is shown as a grey box.