Studies on mammalian chromosome replication. III. Organization and replication of diplochromosomes.

The process of DNA synthesis in normal and endoreduplicating mammalian cells are very similar. Both types of chromosomes are replicated in defined units termed chromosomal replicons, and in the same sequences along their lengths. The sister chromosomes of the diplochromosomes are replicated synchronously in identical patterns. The present observations suggest that organization and sequences of chromosome replication are genetically programmed.