Component of the monopolin complex which promotes monoorientation during meiosis I; required for chromosome segregation during meiosis. Plays also a mitotic role in DNA replication. {ECO:0000269|PubMed:11470404; ECO:0000269|PubMed:12689592; ECO:0000269|PubMed:15023545; ECO:0000269|PubMed:16487579; ECO:0000269|PubMed:18997772}.