The condensin complex is a key determinant of mitotic chromosome architecture. 
In addition, condensin promotes resolution of sister chromatids during anaphase, 
a function that is conserved from prokaryotes to human. Anaphase bridges 
observed in cells lacking condensin are reminiscent of chromosome segregation 
failure after inactivation of topoisomerase II (topo II), the enzyme that 
removes catenanes persisting between sister chromatids following DNA 
replication. Circumstantial evidence has linked condensin to sister chromatid 
decatenation but, because of the difficulty of observing chromosome catenation, 
this link has remained indirect. Alternative models for how condensin 
facilitates chromosome resolution have been put forward. Here, we follow the 
catenation status of circular minichromosomes of three sizes during the 
Saccharomyeces cerevisiae cell cycle. Catenanes are produced during DNA 
replication and are for the most part swiftly resolved during and following 
S-phase, aided by sister chromatid separation. Complete resolution, however, 
requires the condensin complex, a dependency that becomes more pronounced with 
increasing chromosome size. Our results provide evidence that condensin prevents 
deleterious anaphase bridges during chromosome segregation by promoting sister 
chromatid decatenation.