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Chromosome 21

About: Chromosome 21 is a research topic. Over the lifetime, 4736 publications have been published within this topic receiving 206655 citations. The topic is also known as: chr21 & Homo sapiens chromosome 21.


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Book ChapterDOI
TL;DR: Studies which support a key role for SOD1 and APP in the pathogenesis of neural abnormalities observed in individuals with Down syndrome are highlighted.
Abstract: Total or partial trisomy of chromosome 21 occurs with relatively high frequency and is responsible for the occurrence of Down syndrome. Phenotypically, individuals with Down syndrome display characteristic morphological features and a variety of clinical disorders. One of the challenges for researchers in this field has been to ascertain and understand the relationship between the Down syndrome phenotype with the gene dosage effect resulting from trisomy of chromosome 21. Much attention therefore, has been given towards investigating the consequences of overexpressing chromosome 21-linked genes. In particular, an extensive analysis of SOD1 and APP have provided important insights as to how perturbations in the expression of their respective genes may contribute to the Down syndrome phenotype. In this review we will highlight studies which support a key role for SOD1 and APP in the pathogenesis of neural abnormalities observed in individuals with Down syndrome. Central to this relationship is how the redox state of the cell is affected and its consequences to neural function and integrity.

90 citations

Journal Article
TL;DR: It is suggested that abnormalities involving chromosomes 6 and 7 may be a characteristic feature of MM, and Aberrations of chromosome 1, although common in MM, may be part of a general cytogenetic feature in human neoplasia.
Abstract: Chromosome aberrations were analyzed in 4 cases of malignant melanoma (MM) after disaggregation of the tumors with collagenase and short-term culture. In all cell cultures, the MM cells displayed a typical triangular spindle form. The chromosome number was near-diploid in one case and near-triploid in three cases. A total of 27 abnormal chromosomes were identified with the Giemsa banding technique. By far, the most common types of abnormalities were translocations, followed by deletions and isochromosomes. Chromosomes 1, 6, and 7 were found to be most frequently involved in structural aberrations. Markers originating from chromosomes 1 and 6 were found in all four cases, and abnormalities of chromosome 7 were found in three. Each marker chromosome was unique for a given case; no common markers for two or more cases were found. Based on the present results and an analysis of reports on the chromosomal constitution of MM cells in the literature, we suggest that abnormalities involving chromosomes 6 and 7 may be a characteristic feature of MM. Aberrations of chromosome 1, although common in MM, may be part of a general cytogenetic feature in human neoplasia.

90 citations

Journal ArticleDOI
TL;DR: A somatic cell hybrid line containing only human chromosome 21 on a mouse background has been used as the source of DNA for construction of a recombinant phage library and nine independently isolated clones used as probes identified a total of 11 new RFLPs.
Abstract: We have identified and characterized 40 DNA probes detecting restriction fragment length polymorphism (RFLP) on human chromosome 4. Single copy human clones were isolated from a bacteriophage library enriched for chromosome 4 sequences. Each clone was hybridized to somatic cell hybrid DNAs for verification of its species and chromosomal origin and for regional localization. Sequences specific for chromosome 4 were tested for their ability to detect RFLPs in human DNA and their potential utility as genetic markers was assessed. Approximately 263,000 base pairs or 0.13% of the chromosome was screened for sequence variation. The estimate of heterozygosity calculated from this large body of data, H = 0.0021, indicates that the degree of sequence variation on chromosome 4 is comparable to other autosomes. The characterization of these 40 markers has tripled the number of polymorphic loci available for linkage studies on chromosome 4, making it feasible to begin construction of a detailed linkage map that will span the entire chromosome.

90 citations

Journal ArticleDOI
TL;DR: The data support the assumption of additional rearrangements prior to, or in the course of, the recombination event, leading to a loss of the sequences between the involved (AT) repeats on chromosome 22.
Abstract: A reciprocal t(17;22)(q11.2;q11.2) was found in a female patient with neurofibromatosis type 1 (NF1) and in her affected daughter. Sequence analysis of cloned junction fragments traversing the breakpoints allowed the identification of the structures involved in the rearrangement. Aberrant bands in Southern hybridizations of restriction enzyme-digested DNA of the patient pointed to the disruption of the NF1 gene in intron 31. Semispecific polymerase chain reaction analysis of the genomic DNA of the patient with the specific primer anchored at NF1 exon 31 was used to obtain the breakpoint-spanning fragment of the derivative chromosome 17. The intron 31 sequence turned out to be interrupted within a large irregular (AT) repeat. The chromosome 22-derived sequence of the der(17) junction fragment allowed us to identify cosmids of the corresponding region from a chromosome 22-specific cosmid library. With the support of the breakpoint-spanning cosmids, the chromosome 22 region upstream of the fragment carried by the der(17) was characterized. Primers deduced from the sequence of this upstream region were used in combination with a primer in NF1 intron 31 distal to the breakpoint on chromosome 17 to amplify the der(22) junction fragment. The structure of the junction sequences suggested that the translocation had arisen by unequal homologous recombination between (AT)-rich repeats on chromosome 22 and on chromosome 17 in intron 31 of the NF1 gene. However, our data support the assumption of additional rearrangements prior to, or in the course of, the recombination event, leading to a loss of the sequences between the involved (AT) repeats on chromosome 22. In the direct vicinity of these (AT) repeats, two members of a previously undescribed low-copy repetitive sequence have been found, copies of which are also present on human chromosome 13.

90 citations

Journal ArticleDOI
30 Jun 1983-Nature
TL;DR: The construction of a partial cosmid library of the human Y chromosome is reported, isolating 30 unrelated DNA probes that are free of highly repetitive sequences, and examining their reaction pattern on male and female genomic blots.
Abstract: Detailed studies of the role of the mammalian Y chromosome in primary sex determination are limited by the lack of available specific markers and by the fragmentary knowledge of its molecular organization. Y-derived unique DNA sequences could provide powerful analytical tools to probe directly the structure of the Y chromosome and provide a means of searching for specific expressed sequences. We report here the construction of a partial cosmid library of the human Y chromosome. From independent clones we have isolated 30 unrelated DNA probes that are free of highly repetitive sequences, and have examined their reaction pattern on male and female genomic blots. Of the 30 probes tested, six were specific for the Y chromosome. In addition, four probes gave a male-female differential hybridization pattern and the remaining 20, although Y-derived, reacted similarly with both male and female DNA.

90 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202320
202259
202147
202061
201943
201858