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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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Journal ArticleDOI
TL;DR: A large autosomal region has been conserved in the evolution of mouse chromosome 4 and the short arm of human chromosome 1 and identification of such conserved regions will contribute to the understanding of the development of the mammalian genome and could suggest gene location by homology mapping.
Abstract: It is possible to generate interspecific somatic cell hybrids that preferentially segregate mouse chromosomes, thus making possible mapping of mouse genes. Therefore, comparison of the linkage relationships of homologous genes in man and mouse is now possible. Chinese hamster × mouse somatic cell hybrids segregating mouse chromosomes were tested for the expression of mouse enolase (ENO-1; EC 4.2.1.11, McKusick no. 17245), 6-phosphogluconate dehydrogenase [PGD; EC 1.1.1.44, McKusick no. 17220], phosphoglucomutase-2 (PGM-2; EC 2.7.5.1, McKusick no. 17190), and adenylate kinase-2 (AK-2; EC 2.7.4.3, McKusick no. 10302). In man, genes coding for the homologous forms of these enzymes have been assigned to the short arm of human chromosome 1. Analysis of 41 primary, independent, hybrid clones indicated that, in the mouse, ENO-1 and AK-2 are syntenic with PGD and PGM-2 and therefore can be assigned to mouse chromosome 4. In contrast, they were asyntenic with 21 other enzymes including mouse dipeptidase-1 (DIP-1, human PEP-C; EC 3.4.11.*, McKusick no. 17000) assigned to human chromosome arm 1q and mouse chromosome 1. Karyologic analysis confirmed this assignment. These data demonstrate that a large autosomal region (21 map units in the mouse and 51 map units in the human male) has been conserved in the evolution of mouse chromosome 4 and the short arm of human chromosome 1. Identification of such conserved regions will contribute to our understanding of the evolution of the mammalian genome and could suggest gene location by homology mapping.

71 citations

01 Jan 1988
TL;DR: Mice that are trisomic for chromosome 16 offer a genetic model for studies relevant to Down syndrome that may also help to clarify molecular mechanisms involved in Alzheimer's disease.
Abstract: Joseph T. Coyle, Mary Lou Oster-Granite, Roger H. Reeves and John D. Gearhart Joseph T. Coyle, Mary Lou Oster.Granite, Roger H. Reeves and John D. Oearhart are at the Departments of Psychiatry, Neuroscience, Physiology, Cell Biology and Anatomy, Gynecology and Obstetrics and the Developmental Genetics Laboratory, The Johns Hopkins University Sehool of Medicine, Baltimore, MD 21205, USA. Recent findings have implicated genes on human chromosome 21 as important in the pathophysiology of Alzheimer's disease (ADJ. These include the high incidence of the pathological features characteristic of AD in individuals with Down syndrome (trisomy 21) and the localization of both a familial AD gene and the gene encoding amyloid precursor protein on chromo- some 21. Substantial genetic homology exists between human chromosome 21 and mouse chromosome 16, including the gene encoding the amyloid precursor protein. Mice that are trisomic for chromosome 16 offer a genetic model.for studies relevant to Down syndrome that may also help to clarify molecular mechanisms involved in Alzheimer's disease. An understanding of the pathophysiology of Alzheimer's disease (AD) has been hindered by the lack of suitable animal models that could be subjected to rigorous molecular and cellular biological studies since such studies currently are not feasible with humans. While the cognitive impairments observed in aged rodents and primates may reflect compromised central cholinergic function 1, it is generally agreed that AD is a disease process with specific pathological features. Furthermore, the synaptic neurochemical abnormalities of AD can be distinguished from those associated with simple aging 2. Lesion-induced deficits of basal forebrain cholinergic neurons in animals have been informative about the behavioral role and synap- tic pharmacology of this particularly vulnerable neur- onal pathway in AD, but do not recreate the other characteristic pathological features a. Several other neurotransmitter systems, including noradrenergic and somatostatin-containing neurons, are also affected in AD 4's. To date, only humans are known to develop spontaneously the neuropathological and cognitive manifestations of AD. Genetics of Alzheimer's disease Recent studies have provided four lines of evidence that genetic factors are involved in the etiology of AD. First, as discussed in greater detail below, most individuals with Down syndrome (DS; trisomy 21) develop the pathological features of AD by the fourth

71 citations

Journal ArticleDOI
TL;DR: A cosmid containing the human sequence (HOX7) homologous to the mouse homeogene Hox-7 was isolated from a genomic cosmid library, and analysis of chromosomes from two patients with Wolf-Hirschhorn syndrome indicates that the HOX7 locus is deleted.
Abstract: A cosmid containing the human sequence (HOX7) homologous to the mouse homeogene Hox-7 was isolated from a genomic cosmid library. There is only one highly conserved homologous gene in the human genome. The C-terminal two-thirds of the HOX7 homeobox DNA sequence has been determined; there are no predicted amino acid changes from the mouse sequence. Data from mouse/human hybrid cell lines show that HOX7 maps to human chromosome 4p16.1, a region that is syntenic with part of mouse chromosome 5, the site of the murine Hox-7 gene. Analysis of chromosomes from two patients with Wolf-Hirschhorn syndrome, which is characterised by profound dysmorphologies, indicates that the HOX7 locus is deleted. Although not all Wolf-Hirschhorn syndrome patients analysed were deleted for HOX7, the combination of positional data and functional correlation with mouse expression implicates HOX7 as a candidate gene for this syndrome.

71 citations

Journal ArticleDOI
TL;DR: Quantitative analysis of neural crest progenitors of the mandible revealed a paucity of NC and a smaller first pharyngeal arch in Ts65Dn as compared to euploid embryos, and results implicate common cellular and molecular bases of multiple DS phenotypes.

71 citations

Journal Article
TL;DR: The magnitude of DNA content differences among normal chromosomes of the same type is demonstrated by Hoechst 33258 versus chromomycin A3 bivariate flow karyotypes and indicates that variability in their copy number is partly responsible for peak-position variability in some chromosomes.
Abstract: Maternal and paternal homologues of many chromosome types can be differentiated on the basis of their peak position in Hoechst 33258 versus chromomycin A3 bivariate flow karyotypes. We demonstrate here the magnitude of DNA content differences among normal chromosomes of the same type. Significant peak-position differences between homologues were observed for an average of four chromosome types in each of the karyotypes of 98 different individuals. The frequency of individuals with differences in homologue peak positions varied among chromosome types: e.g., chromosome 15, 61%; chromosome 3, 4%. Flow karyotypes of 33 unrelated individuals were compared to determine the range of peak position among normal chromosomes. Chromosomes Y, 21, 22, 15, 16, 13, 14, and 19 were most heteromorphic, and chromosomes 2-8 and X were least heteromorphic. The largest chromosome 21 was 45% larger than the smallest 21 chromosome observed. The base composition of the variable regions differed among chromosome types. DNA contents of chromosome variants determined from flow karyotypes were closely correlated to measurements of DNA content made of gallocyanin chrome alum-stained metaphase chromosomes on slides. Fluorescence in situ hybridization with chromosome-specific repetitive sequences indicated that variability in their copy number is partly responsible for peak-position variability in some chromosomes. Heteromorphic chromosomes are identified for which parental flow karyotype information will be essential if de novo rearrangements resulting in small DNA content changes are to be detected with flow karyotyping.

71 citations


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