A model for the efficient distribution of licensed origins. Events occurring on DNA (solid black line) as origins are licensed during anaphase and replicate during S phase. (A) ORC and Cdc6 bind to an unlicensed origin. (B) The origin is licensed by loading an Mcm2–7 double hexamer (M). (C) The binding of Mcm2–7 destabilizes ORC, Cdc6, and Cdt1 at that site so they can be displaced to a new site on the chromosome. (D) ORC and Cdc6 are exported out of the interphase nucleus, whereas Cdc45 is recruited to Mcm2–7 when replication forks initiate.