PubMed HealthSearch

PubMed · 90591

Relation between the SCE points and the DNA replication bands.

Abstract

A method for obtaining a combination of differential sister chromatid staining and DNA replication banding is described. Using this method the SCE points can be precisely localized to particular bands of individual chromosomes. It was shown, that SCEs occur not only in the regions of early DNA replication (= euchromatic segments = negative G-bands), but also in the regions of late DNA replication bands (=heterochromatic segments=positive G-bands). SCEs occurred about three times more frequently in the euchromatic segments than in the heterochromatic segments. Furthermore, more SCEs were observed in the early replicating X-chromosome than in the late replicating X-chromosome.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J J Hoo, M I Parslow. 1979-06-21. Relation between the SCE points and the DNA replication bands.. https://doi.org/10.1007/bf00294846

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Quantitative studies on the arrangement of human metaphase chromosomes. VII. The association pattern of acrocentric chromosomes in carriers of Robertsonian translocations and in their relatives with normal karyotypes.

The pattern of association of acrocentric chromosomes was examined in ten and five carriers of a 15/21 and a 13/14 Robertsonian translocation, respectively, and was compared with that of the same numbers of relatives with normal karyotypes. In the carriers of 15/21 translocation, the number of large associations (involving more than two acrocentrics) and the association frequencies for individual acrocentric chromosomes, were significantly higher than in the control group. The mean number of associations of the single homologs of the translocation chromosomes was much higher than that of the other acrocentrics. In the carriers of 13/14 translocations, only the association frequency for chromosome 13 was higher than in the normal relatives. The uninvolved chromosomes homologous to those involved in translocation showed an insignificant increase in associations in comparison with the other acrocentrics. These results suggest that some mechanism within the cells compensates for the effect of missing acrocentrics or of acrocentrics lacking NORs on the number of associations. The possible relations of this phenomenon to the activity of the nucleolus organizing regions are discussed.

Chromosome Banding

Simultaneous staining of sister chromatid exchanges and Q-bands in human chromosomes after treatment with methyl methane sulphonate, quinacrine mustard, and quinacrine.

Human peripheral lymphocyte chromosomes were stained simultaneously for sister chromatid exchanges (SCEs) and Q-banding. No effect of treatment with MMS, QM, and Q on the distribution of SCEs in chromosomes was found compared with controls. The SCEs were distributed between chromosomes roughly according to metaphase length, with the shorter chromosomes underrepresented. The majority of SCEs were located to pale bands, while a few occurred in bright bands and at interfaces between pale and bright bands. A greater frequency than expected of SCEs had occurred at identical sites in homologous chromosomes. This frequency was significantly increased after treatment with MMS.

Chromosome Banding