STAG domain proteins are subunits of cohesin complex - a proteincomplex required for sister chromatid cohesion in eukaryotes.The STAG domain is present in Schizosaccharomyces pombe mitoticcohesin Psc3, and the meiosis specific cohesin Rec11. Manyorganisms express a meiosis-specific STAG protein, for example,mice and humans have a meiosis specific variant called STAG3,although budding yeast does not have a meiosis specific version[1].