A Direct Approach to the Structure of Eukaryotic Chromosomes (original) (raw)

1. J. Sedat and
2. L. Manuelidis
3. Radiobiology Laboratories and Pathology Department, Yale University School of Medicine, New Haven, Connecticut 06510

Excerpt

The higher orders of organization of eukaryotic genomes, both structural and with respect to specific DNA sequences, are not yet clear. One of the most intriguing problems about which little is known is the organization of chromosomes in the interphase nucleus. During interphase, replication of the DNA takes place and, in addition, specific transcription directed by developmentally controlled patterns occurs. It is likely that in the interphase nucleus structure and function are coordinated in a carefully orchestrated manner, and the interphase nucleus should be capable of dynamic changes. Two extremes in model interphase systems can be considered for study. One of these is the polytene system in Drosophila, where early in development a group of cells are set aside and no longer divide, but instead continue to replicate their DNA in a straightforward geometric manner leading to greatly enlarged (1024C) interphase nuclei characterized by banded giant chromosomes (Beermann 1962). On...