David Morgan’s group found that segregation time of chromosomes 4 and 5 is significantly elongated in budding-yeast strains with mutations in the 2 N-terminal securin phosphorylation sites and securin deletion strains. In addition, these mutant strains exhibited very high rates of mis-segregation compared to normal behavior. Switch-like characteristics are necessary to trigger quick, coordinated chromosomal segregation in anaphase. This means that strong inactivation of separase by securin followed by sudden, rapid destruction of securin and activation of separase is vital for proper anaphase.