On the replicative organization of DNA in the polytene chromosome of Drosophila melanogaster

LIMITED DNA SYNTHESIS IN THE ABSENCE OF PROTEIN SYNTHESIS IN PHYSARUM POLYCEPHALUM

“…In most higher organisms, replication takes place at numerous points along particular chromosomes at given times (18,25). Plaut and Nash (19) suggested that the points of replication along the polytene chromosomes of Drosophila may be formed by independently replicating units.…”

“…Jacob and Brenner (7) proposed an elegant hypothesis which explains bacterial DNA replication in terms of a positive control mechanism. Many eukaryotes show, however, a more complicated design of replication than do the prokaryotes (18,25,26). The evidence suggests that neither replication of the genome nor even replication of a chromosome is regulated by a single complex with properties similar to those of the bacterial replicon.…”

ON THE PRESENCE OF DNA IN LARVAL SALIVARY GLAND NUCLEOLI IN DROSOPHILA MELANOGASTER

“…Like the fluorescing elements, nucleolar label appears randomly distributed. Nucleolar labeling is characteristically associated with dense (continuous [11]) patterns of chromosomal thymidine incorporation. Figs.…”

A Locked-Loop Configuration in Salivary-Gland Chromosome 2R of <i>Drosophila melanogaster</i>

“…Any adjustments must be met within the confines of the individual homologues. As noted by Plaut (1963) and Gay (1963) the synthesis of DNA may be initiated at several widely spaced points along the chromosomes. The mechanics of DNA and protein synthesis must accordingly be visualized in terms of localized activity in the closed system under consideration.…”