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Chromosome

About: Chromosome is a research topic. Over the lifetime, 17538 publications have been published within this topic receiving 660077 citations. The topic is also known as: chromosomes & GO:0005694.


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Journal ArticleDOI
13 Jan 1968-Nature
TL;DR: It seems to be a rule of chromosome replication that heterochromatin synthesizes its DNA at a later stage than the rest of the chromosome.
Abstract: It seems to be a rule of chromosome replication that heterochromatin synthesizes its DNA at a later stage than the rest of the chromosome.

254 citations

Journal ArticleDOI
01 Aug 1995-Genetics
TL;DR: These findings showed that the major Nor loci have repeatedly changed position in the chromosome arms during the radiation of species in the tribe Triticeae without rearrangements of the linkage groups.
Abstract: The nucleolus organizing regions (NORs) on the short arms of chromosomes 1A(m) and 5A(m) of diploid wheat, Triticum monococcum L., are at the most distal loci in the linkage maps of these two chromosome arms. This distal location differs from the interstitial location of the Nor loci on chromosome arms 1BS of tetraploid Triticum turgidum L. and hexaploid T. aestivum L., 5DS of T. aestivum and diploid Ae. tauschii Coss., and 5HS of barley. Moreover, the barley 5HS locus is at a different location than the 5DS locus. However, other markers, including the centromeres, are colinear. These findings showed that the major Nor loci have repeatedly changed position in the chromosome arms during the radiation of species in the tribe Triticeae without rearrangements of the linkage groups. It is suggested that Nor loci may change position via dispersion of minor loci, that are shown here to exist in the T. monococcum genome, magnification of gene copy numbers in these minor loci, and subsequent deletion of the original major loci. Implications of these findings for the use of rRNA nucleotide sequences in phylogenetic reconstructions are pointed out.

254 citations

Journal Article
TL;DR: The modeling studies suggest that the overrepresentation of individual oncogene-bearing chromosomes in aneuploid cell lines may require the activation of gene dose-dependent growth-promoting genes and is not likely to occur in cell lines in which at least two copies of each normal chromosome are required for cell survival.
Abstract: A conceptual model is proposed for the genetic evolution of many human solid tumors that is based on the observations that cancer cells may spontaneously double their chromosome number; that cells with excessive chromosome numbers may be cytogenetically unstable, both losing chromosomes randomly during subsequent cell divisions, and often developing structural abnormalities in the chromosomes that are retained; and that some structural chromosome abnormalities may activate growth-promoting genes. The sequence of tetraploidization with chromosome loss can occur repeatedly in a given tumor. The available evidence supporting the model is reviewed. A computer simulation system that embodies these concepts is described and the model is used to generate distributions of chromosome number/cell under various simulated conditions and in a variety of simulated biological settings. A simulation of the time course of changes in chromosome number per cell that accompany the spontaneous neoplastic transformation of mouse fibroblasts in vitro is described. The best fit to the data was obtained when provision was made for the activation of at least two growth-promoting genes. The conditions for generating discrete aneuploid peaks in cytogenetic and flow cytometric studies were explored; our modeling studies suggest that the activation of a growth promoting gene is required in order to produce a discrete aneuploid peak. Our modeling studies suggest that the overrepresentation of individual oncogene-bearing chromosomes in aneuploid cell lines may require the activation of gene dose-dependent growth-promoting genes and is not likely to occur in cell lines in which at least two copies of each normal chromosome are required for cell survival. Overall, the results obtained using the model are consistent with a wide variety of flow cytometric and cytogenetic studies in human solid tumors.

253 citations

Journal Article
TL;DR: These tumors suggest that at least 2 regions of chromosome 6 are important for ovarian epithelial carcinogenesis and one region appears to be on distal 6q and a second region is near the centromere of chromosomes 6 proximal to the HLA locus.
Abstract: To determine which chromosomes and chromosomal regions contain putative tumor suppressor genes important for human epithelial ovarian cancer, we performed loss of heterozygosity (LOH) studies on 37 primary epithelial ovarian tumors. Using 70 polymorphic markers, we examined all chromosome arms (excluding acrocentric arms) on all specimens. Our findings show a high frequency of LOH for the following chromosome arms: 5q (43%); 6p (62%); 6q (57%); 7p (36%); 8p (40%); 9q (54%); 13q (56%); 14q (47%); 15q (36%); 17p (81%); 17q (76%); 18q (43%); 21q (36%); and 22q (71%). When separated into low and high grade tumors, there were statistically significant differences of LOH for the following chromosome arms: 6p (29% versus 70%); 13q (0% versus 72%); 17p (33% versus 90%); and 17q (29% versus 87%). No statistically significant difference was found between different histological subtypes. The average fractional allelic loss for low grade tumors was 0.17 versus 0.40 for high grade and 0.35 for all tumors. In an effort to more specifically localize common regions of molecular genetic deletion, we examined the following chromosomes in greater detail: chromosome 13 (5 markers); chromosome 17 (8 markers); and chromosome 6 (8 polymorphic markers). No tumor showed deletion of only a portion of chromosome 13. When any informative marker for chromosome 13 showed loss, all markers showed loss. Similarly, the tumors of most patients demonstrated LOH of all informative markers that map to chromosome 17; however, regional deletion of 17p markers was observed in 3 tumors. Twelve tumors demonstrated regional deletions of portions of chromosome 6. These tumors suggest that at least 2 regions of chromosome 6 are important for ovarian epithelial carcinogenesis. One region appears to be on distal 6q and a second region is near the centromere of chromosome 6 proximal to the HLA locus.

251 citations

Journal ArticleDOI
01 Jul 1992-Genomics
TL;DR: One hundred highly informative simple sequence repeat (SSR) polymorphisms have been isolated and mapped to specific human chromosomes by somatic cell hybrid analysis and at least one SSR was detected on every chromosome.

251 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023862
20221,198
2021368
2020359
2019365