Abstract
EMBO J 31 9, 2076–2089 March 13 2012 EMBO J 31 9, 2090–2102 March 13 2012 It is well known that somatic and germ cells use different cohesin complexes to mediate sister chromatid cohesion, but why different isoforms of cohesin also co-exist within somatic vertebrate cells has remained a mystery. Two papers in this issue of The EMBO Journal have begun to address this question by analysing mouse cells lacking SA1, an isoform of a specific cohesin subunit.