Showing papers on "Chromosome 21 published in 1974"

Human Chromosome 21 Dosage: Effect on the Expression of the Interferon Induced Antiviral State

Abstract: Human primary skin fibroblasts trisomic for chromosome 13, 18, or 21 and diploid human skin fibroblasts were induced for an antiviral response with human interferon. The cells that were trisomnic for chromosome 21 were three to seven times more sensitive to protection by human interferon than the normal diploid or trisomic 18 or 13 fibroblasts. The differential response in trisomnic 21 cells is consistent with the known assignment of the human antiviral gene to chromosome 21.

The sex chromosomes of the Chinese hamster: constitutive heterochromatin deficient in repetitive DNA sequences.

Abstract: Portions of constitutive heterochromatin of the Chinese hamster Cricetulus griseus, do not appear to contain a disproportionately high amount of repeated DNA sequences. These specific regions are the long arm of the X chromosome, the entire Y chromosome, and the centromeric region of chromosome 10. Other heterochromatic areas of the Chinese hamster chromosomes showed localization of repetitious DNA.

Variation of spontaneous occurrence rates of chromosomal aberrations in the second chromosomes of Drosophila melanogaster.

Abstract: After accumulating mutations by the aid of marked inversions, spontaneous occurrence rates of chromosome aberrations were estimated for 1148 chromosome lines that originated from five stem line second chromosomes of Drosophila melanogaster. In chromosome lines originating from three stem chromosomes (CH, PQ, and RT), mutations were accumulated for 7550, 7252, and 7256 chromosome generations, respectively, but no structural change was detected. For the chromosome lines that originated from the other two stem chromosomes, the situation was different: Twenty aberrations (19 paracentric inversions and 1 translocation between the second and the third chromosomes) during 45990 chromosome generations took place in the 500 chromosome lines derived from stem line chromosome (AW), and 92 aberrations (83 paracentric inversions, 6 pericentric inversions, 2 translocations between the second and the third chromosomes and 1 transposition) arose during 45006 chromosome generations in the 500 chromosome lines derived from stem line chromosome (JH). For the AW group the occurrence rate becomes 0.00043 per chromosome per generation for all aberrations and 0.00041 for inversions. For the JH group the corresponding rates are 0.00204 and 0.00198, respectively.-A non-random distribution of the breakpoint on the salivary gland chromosome was observed and the breakpoints were concentrated in the regions 26, 29, 33, and 34.-The cytoplasms and the chromosomes (other than the second chromosomes) were made approximately uniform throughout the experiments. Thus, this remarkable variability in the occurrence rate is most probably due to the differences in one or more chromosomal elements on the original five stem chromosomes. The mutable chromosomes (AW and JH) appear to carry a kind of mutator factor such as hi (Ives 1950).

Partial trisomy 12 in a mentally retarded boy and translocation (12;21) in his mother

Abstract: Cytogenetic studies of an infant with malformations and a peculiar appearance showed a partial trisomy of chromosome 12. The mother carried a translocation of the distal part of chromosome 12 onto the short arm of chromosome 21, with breakpoints most likely at 12q24 and 21p11.

Trisomy of the short arm of chromosome 17.

Abstract: The chromosome analysis of a female newborn with multiple malformations revealed an extra, small acrocentric chromosome that is smaller than the G-group chromosomes. Using special staining techniques, we identified the extra chromosome as the short arm of chromosome 17.

Directed Chromosome Loss by Laser Microirradiation

Abstract: In this article I have presented data that indicate the feasibility of attaining the five objectives outlined in the introduction. It should be possible to assign genes to specific chromosome regions by (i) selective DNA deletion of a 0.25- to 0.5-µ.m segment of one or both homologous chromosomes, (ii) deletion of one or both entire homologous chromosomes, or (iii) combining cell fusion with selective deletion of whole chromosomes and then deletion of chromosome segments. By laser microirradiation it should be possible to determine which chromosomes and chromosome regions are essential for immediate cell survival by removing from individual cells whole chromosomes, and chromosome segments from each of the chromosomes in the karyotype, and then assessing the cloning efficiency of each cell. For example, we have already determined that removal of one large chromosome No. 1 from PTK2 cells does not prevent the cell from undergoing a subsequent mitosis. It should also be possible to generate new classes of mutants by damaging small selected areas of DNA with the laser beam and then cloning the irradiated cells—but this has yet to be demonstrated. This procedure might reveal recessive alleles on the nonirradiated homolog, or might result in the direct production of a genetic mutation. Irradiation of identical places on both homologous chromosomes could result in deletion of a genetic locus which ultimately might be detected as a deficiency in a metabolic pathway or some other cellular abnormality. Studies on chromosome stability and DNA constancy can be conducted with laser irradiated cells. For example, the karyotypic analysis of chromosome No. 1 suggests that a cellular mechanism exists to maintain the constancy of this chromosome in both the diploid and tetraploid cell lines. The same approach could be used with each of the chromosomes in the karyotype. Various cytochemical procedures could be used for making quantitative DNA studies of the cells, and chromosome and DNA analyses could be performed at varying times following laser microirradiation. It might also be possible to study the repair of chromosomal damage caused by laser irradiation. The cells could be examined by autoradiographic, cytochemical, and electron microscopy procedures at varying times after irradiation, and because the precise location, time, and nature of the mutational event would be known, subsequent analysis of repair and alteration would be facilitated.

Monosomy for the centromeric and juxtacentromeric region of chromosome 21.

Abstract: A boy with partial monosomy 21 is described. The child has an unbalanced 20/21 translocation with deletion of the centromeric and juxtacentromeric region of chromosome 21. Examination by C-banding technique shows that the translocation is of maternal origin. Investigation of a number of genetic marker systems shows that the HL-A, AcP, and GPT loci are not located in the deleted segment.

Down's syndrome associated with two Robertsonian translocations, 45,XX,−15,−21,+t(15q21q) and 46,XX,−21,+t(21q21q)

Abstract: A female infant with Down's syndrome was found to be a chromosomal mosaic with two cell lines in both blood and skin cells. One line carried a balanced 15/21 translocation, and the other line was effectively trisomic for chromosome 21 with a 21/21 translocation.

Deletion of the long arms of the Y chromosome with normal male development and intelligence

Abstract: Normal male development was found in a man with a proven deletion of the long arms of the Y chromosome. The only phenotypic effect was on his build. This study offers additional proof that all, or most of the long arms of the Y chromosome are not primarily concerned with the determination of male sexual characteristics.

An unusual chromosomal segregation in a family with a translocation between chromosomes 3 and 12

Abstract: A family is reported in which two infants were born with different types of congenital abnormalities. Chromosome studies on one of the infants showed a partial trisomy of the short arms of a No. 3 chromosome. A family study showed many balanced translocation carriers who had extra chromosomal material on the long arms of a No. 12 chromosome.

Meiosis in male drosophila melanogaster i. isolation and characterization of meiotic mutants affecting second chromosome disjunction

Abstract: Two second chromosome, EMS-induced, meiotic mutants which cause an increase in second chromosome nondisjunction are described. The first mutant is recessive and causes an increase in second chromosome nondisjunction in both males and females. It causes no increase in nondisjunction of the sex chromosomes in either sex, nor of the third chromosome in females. No haplo- 4 -progeny were recovered from either sex. Thus, it appears that this mutant, which is localized to the second chromosome, affects only second chromosome disjunction and acts in both sexes.—The other mutant affects chromosome disjunction in males and has no effect in females. Nondisjunction occurs at the first meiotic division. Sex chromosome disjunction in the presence of this mutant is similar to that of sc 4 sc 8 , with an excess of X and nullo- XY sperm relative to Y and XY sperm. In some lines, there is an excess of nullo- 2 sperm relative to diplo- 2 sperm, which appears to be regulated, in part, by the Y chromosome. A normal Y chromosome causes an increase in nullo- 2 sperm, where B s Y does not. There is also a high correlation between second and sex chromosome nondisjunction. Nearly half of the second chromosome exceptions are also nondisjunctional for the sex chromosomes. Among the double exceptions, there is an excess of XY nullo- 2 and nullo- XY diplo- 2 gametes. Meiotic drive, chromosome loss and nonhomologous pairing are considered as possible explanations for the double exceptions.

Serum polymorphisms in Down's syndrome.

Abstract: The phenotype frequencies of serum haptoglobin, serum group specific protein, the second (slower) running zone of the serum leucine naphthylamidase and the serum alkaline phosphatase types of a large sample of subjects with Down's syndrome (254 subjects) are compared with a series of mentally subnormal controls. No phenotype shift could be observed for the haptoglobins, but the frequencies of the serum Gc proteins of the Down's subjects were significantly different to that of the controls. Further investigation of the Gc proteins demonstrated reduced concentrations in the Down's subjects (P=0.05) which together with the failure to establish any change in association between the Gc phenotype contradicts the location of the gene for the Gc proteins being located on the 21st chromosome

Multiple congenital defects associated with trisomy for the short arm of chromosome 4

Abstract: The clinical and cytogenetic findings of a female infant with multiple congenital anomalies and trisomy for the short arm of chromosome 4(46,XX,21p+) are described. The abnormal chromosome was inherited from the father who had a balanced translocation between the short arm of chromosome 4 and the short arm of chromosome 21. Clinical features are compared with those of one definite and one probable previously described case of trisomy for the short arm of chromosome 4. It is suggested that a clinical syndrome associated with +4p eventually may be identified.

Rare translocation 47,XY,t(12;21) in Down's syndrome.

Abstract: A translocation between the long arm of chromosome 12 and the long arm of chromosome 21 was found in a male with typical Down’s syndrome. His mother and a maternal uncle carried the same translocation

A 21/21 tandem translocation with satellites on both long and short arms

Abstract: We report a case of 21/21 tandem translocation resulting in a chromosome with satellites on both the long and short arms, in a patient with relatively few stigmata of Down's syndrome.

Variations of centromeric region of chromosome no. 1 and no. 9 in one family.

Abstract: The karyotype of a young man with a complex of congenital malformations is described. An enlarged area of centromeric heterochromatin was found in one chromosome No. 1 and one chromosome No. 9. The same variation was found in one chromosome No. 9 in the patient's step-sister and her son. The possible connection between their phenotypes and these types of variations is discussed.

Numbers of Chromosomes in Human Leucocytes Exposed to Ecdysterone

Abstract: All chromosomes could not be identified with certainty until relatively recently even with radiolabeling. Differential patterns in staining heterochromatin were then obtained by Gall and Pardue (1971) and others (Gagne et al., 191). In addition, Caspersson and colleagues (Caspersson and Zech, 1972) and others have used fluorescent banding that appears with ultra-violet illumination of chromosomes stained with quinacrine mustard to characterize each chromosome uniquely. This has clarified quickly some confusion in karyotyping syndromes of clinical significance. For example, trisomic chromosome 21 (newer terminology) in Down’s disease proved to be distinct from the Philadelphia chromosome now known to be chromosome 22 with a portion deleted. Previously the postulate that the same chromosome was involved in both abnormalities was attractive, since both are associated with neoplastic disease. Quinacrine mustard was selected on the basis of the supposition that it would bind to one of the nitrogen atoms in the guanine base of the nucleotide (Casperson et al., 1967). However, the bands that fluoresce do not correspond to the distribution of DNA determined spectrophotometrically, and the reason for differential regional affinity is not entirely clear at the present time.