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Showing papers on "Chromosome 21 published in 1973"


Journal ArticleDOI
TL;DR: Subclones of this line indicate that the loci for PGD and PGM1 are situated on the short arm or proximal part of the long arm of 1 and the locus for Pep-C on the longArm of 1, which places the PGD loci on chromosome 6.
Abstract: About 75 man-Chinese hamster hybrid clones were analysed for their human chromosome complement and simultaneously tested for human enzyme markers. Correlation of the presence of chromosomes and enzyme activity revealed assignments of the PGD linkage group to chromosome 1, ME1, PGM3 and IPO-B to 6, LDH-A to 11, LDH-B to 12 and IPO-A to 21.

97 citations


Journal ArticleDOI
TL;DR: A mechanism is proposed to explain the cytogenetic data on inactivation and the derivation of the eutherian system from the marsupials and the response of the sensitive site to its passage through the male may be designated as imprinting.
Abstract: In female mammals, one of the two X chromosomes present is inactivated during early development. In marsupials, the paternal X is inactivated; in eutherians, one of the two X chromosomes is inactivated at random. A mechanism is proposed to explain the cytogenetic data on inactivation and the derivation of the eutherian system from the marsupial system. In the marsupial system, a site on the X chromosome is sensitive to paternal origin: when the X chromosome is of maternal origin, this sensitive site is responsible for influencing an adjacent site, the receptor, to maintain the X in an active state; the paternal X becomes inactive. Transposition of the sensitive site to an autosome in eutherians would have two consequences. Since the receptor site of the X chromosome is no longer adjacent, the autosomal sensitive site of maternal origin would activate an X at random. The number of active X chromosomes would conform to the number of maternal sensitive sites and thus, generally, to the number of maternal sets of autosomes. The response of the sensitive site to its passage through the male may be designated as imprinting, a term used by Crouse to indicate that the behavior of Sciara chromosomes is determined by parental origin.

79 citations



Journal ArticleDOI
TL;DR: Fluorescence and Giemsa banding showed loss of chromosomal material from the distal part of chromosome No. 6 in a severely mentally and physically retarded patient with a peculiar appearance.
Abstract: A translocation of the long arm of chromosome No. 15 onto the long arm of chromosome No. 6 was observed in a severely mentally and physically retarded patient with a peculiar appearance. Fluorescence and Giemsa banding showed loss of chromosomal material from the distal part of chromosome No.6; 45,XY,tan(6;15) (6pter→6q25::15q12→15pter). The proband's father and brothers showed hyperdiploid cells and cells with rearrangements. Regular Down's syndrome was observed in a first cousin once removed.

40 citations


Journal ArticleDOI
TL;DR: A case report on an infant with trisomy of the distal third of the long arm of chromosome No. 7 is presented.
Abstract: A case report on an infant with trisomy of the distal third of the long arm of chromosome No. 7 is presented.

29 citations


Journal ArticleDOI
TL;DR: The clinical features and laboratory findings in patients with deletion of a chromosome from the “G” group are described with details of a new case which reveals hitherto unrecognised features.
Abstract: Summary The clinical features and laboratory findings in patients with deletion of a chromosome from the “G” group are described with details of a new case which reveals hitherto unrecognised features. Special studies using the chromatin banding technique have shown that the patient's tissues have partial or complete deletion of a chromosome 21.

24 citations


Journal ArticleDOI
TL;DR: There is a susceptibility for breakage of the long arms of the number 9 chromosome at the junction of the heterochromatin and euchromatin area closest to the centromere in a male infant observed with a complex of clinical abnormalities.
Abstract: A male infant was observed with a complex of un usual clinical abnormalities. Chromosomal studies revealed that the child was mosaic for a chromosomal fragment from the long arms of a number 9 chromosome. The majority of cells contained 46 chromosomes with a partially deleted number 9 chromosome and a chromosomal fragment. From these data and others repor ted, it would appear that there is a susceptibility for breakage of the long arms of the number 9 chromosome at the junction of the heterochromatin and euchromatin area closest to the centromere. The lymphocytes from this child are capable of transformation into long-term lymphocyte cultures, and after many months in culture the chromosomal fragment has replicated in the cultured cells even though it contained no detectable centromere.

22 citations


Journal ArticleDOI
TL;DR: The results suggest the following gene sequence on chromosome A1: 6 PGD, PGM1 ( on the short arm), Pep C (on the long arm) may be associated with human-Chinese hamster hybrid cell line.
Abstract: A human-Chinese hamster hybrid cell line was treated with X-rays and subsequently cloned. In two clones, segregation between three markers assigned to the human A1 chromosome (6-phosphogluconate dehydrogenase, phosphoglucomutase 1 and peptidase C) was found. Chromosome analysis revealed an aberrated human A1 chromosome in both clones. The results suggest the following gene sequence on chromosome A1: 6 PGD, PGM1 (on the short arm), Pep C (on the long arm).

22 citations


Journal ArticleDOI
TL;DR: Cytogenetic analysis shows that the human gene loci PGM(1) and 6PGD are located on the short arm of chromosome one distal to the break point, while Pep C lies elsewhere on the chromosome.
Abstract: The human gene loci phosphoglucomutase1 (PGM1, EC 2.7.5.1) and 6-phosphogluconate dehydrogenase (6PGD, EC 1.1.1.43), which are located on human chromosome one, have been assigned to a specific region of the short arm of that chromosome, by use of a hybrid cell line derived from a Chinese hamster cell line deficient in hypoxanthine phosphoribosyl transferase and a strain of human diploid fibroblasts. Cytogenetic analysis of a hybrid clone maintained for about 50 generations in vitro revealed two populations of cells, the first containing a human chromosome one with a break point at band 1p33, such that about 25% of the short arm of this chromosome was deleted. The second cell population contained a normal chromosome one. Biochemical analysis of subclones derived by cloning this mixed population revealed two phenotypic classes, one of which expressed all three chromosome-one markers, PGM1, 6PGD, and peptidase C (Pep C), while the other expressed only Pep C. Cytogenetic analysis showed that the subclones expressing all three markers carried the normal human chromosome one, while those expressing only Pep C carried the deleted chromosome. These data indicate that the human gene loci PGM1 and 6PGD are located on the short arm of chromosome one distal to the break point, while Pep C lies elsewhere on the chromosome.

20 citations





Journal ArticleDOI
TL;DR: Analysis of two normal males and an XYY individual revealed no evidence to support the contention that the Y chromosome consistently assumes a peripheral location in metaphase cells.
Abstract: It has been reported that the Y chromosome consistently assumes a peripheral location in metaphase cells. Analysis of two normal males and an XYY individual revealed no evidence to support this contention.

Journal ArticleDOI
TL;DR: The specific adenovirus type-12 induced aberration in chromosome No. 17 has been used to identify this autosome in cells from patients with No.17/18 (E group) chromosome abnormalities.
Abstract: The specific adenovirus type-12 induced aberration in chromosome No. 17 has been used to identify this autosome in cells from patients with No. 17/18 (E group) chromosome abnormalities. The results show that all the cases examined involved abnormalities of chromosome No. 18.

Journal ArticleDOI
TL;DR: Fluorescent microscopy after staining with quinacrine mustard revealed that what appeared to be a simple inversion of a G chromosome as judged by conventional cytogenetic techniques actually represented a probable reciprocal translocation resulting in monosomy-21 and trisomy of the centric portion of another chromosome.
Abstract: A patient with a complex chromosomal rearrangement is described. Fluorescent microscopy after staining with quinacrine mustard revealed that what appeared to be a simple inversion of a G chromosome as judged by conventional cytogenetic techniques actually represented a probable reciprocal translocation resulting in monosomy-21 and trisomy of the centric portion of another chromosome. The congenital abnormalities noted were: hypertelorism, epicanthus, small ears, small mouth, high-arched palate, flat nasal-bridge, and short neck. Several joints, including those in the fingers and toes, were malformed and limited in their movements. There was a heart anomaly interpreted as a ventricular septal defect and psychomotor development at the age of 14 months was clearly retarded. The clinical features of this patient were compared with the cases reported by others in which total or partial G-monosomy was claimed.

Journal ArticleDOI


Journal ArticleDOI
TL;DR: 4 cases of “? chromosome abnormality”, referred to this department in the past 3 months, have shown an aberrant complement of chromosome 18.
Abstract: 4 cases of “? chromosome abnormality”, referred to this department in the past 3 months, have shown an aberrant complement of chromosome 18. Chromosome 18 has been identified using a modification of Seabright's (1971) method of banding human chromosomes.

Journal ArticleDOI
TL;DR: Chromosome No. 21 consistently shows a lighter C band at the centromere than chromosome No. 22, allowing reliable differentiation, and was demonstrated in karyotypes with centric fusions t(Dq 21q), trisomy 21 and by comparing the C-and Q-band polymorphism of the short arms of the G chromosomes.
Abstract: Chromosome No. 21 consistently shows a lighter C band at the centromere than chromosome No. 22, allowing reliable differentiation. This distinction was demonstrated in karyotypes with centric fusions t(Dq 21q), trisomy 21 and by comparing the C-and Q-band polymorphism of the short arms of the G chromosomes.