Spontaneous fragility of an abnormally wide secondary constriction region in a human chromosome No. 9

1969 ◽  
Vol 7 (1) ◽  
pp. 22-27 ◽  
Author(s):  
W. Schmid ◽  
D. Vischer
Keyword(s):  
Human Chromosome ◽  
Secondary Constriction ◽  
Constriction Region

Molecular characterization of the secondary constriction region (qh) of human chromosome 9 with pericentric inversion

1992 ◽  
Vol 103 (4) ◽  
pp. 919-923
Author(s):  
S. Luke ◽  
R.S. Verma ◽  
R.A. Conte ◽  
T. Mathews
Keyword(s):  
Human Chromosome ◽  
Dna Sequences ◽  
Pericentric Inversion ◽  
Secondary Constriction ◽  
Hierarchical Organization ◽  
Chromosome 9 ◽  
Direct Function ◽  
Alphoid Dna ◽  
Pericentric Inversions ◽  
Constriction Region

Pericentric inversion of the secondary constriction region (qh) of human chromosome 9 is a frequent occurrence. This structural alteration is regarded as a normal familial variant, termed heteromorphism, and is inherited in a Mendelian fashion without any apparent phenotypic consequences. We characterized the qh region of chromosome 9 from five individuals using a series of molecular cytogenetic techniques. Four out of the five individuals have an additional area composed of alphoid DNA sequences on the inverted chromosome 9 while one case was found to have an apparently intact alphoid DNA sequence. Although the direct function(s) of alphoid DNA sequences remain unclear, the centromeric breakage involving these sequences in inverted chromosome 9 raises a series of questions pertaining to the monocentric, dicentric and pseudodicentric nature of pericentric inversions. Nevertheless, these findings have prompted us to suggest that the structural organization of alphoid DNA sequences of the centromeric region of chromosome 9 are apparently “breakage prone” and may be associated with a higher incidence of pericentric inversions. Furthermore, the hierarchical organization of various satellite DNA families (alpha-satellite, beta-satellite and satellite III) within the primary and secondary constriction regions of chromosomes 9 are elucidated here.

Mechanisms of the origin of a G-positive band within the secondary constriction region of human chromosome 9

1995 ◽  
Vol 69 (3-4) ◽  
pp. 235-239 ◽  
Author(s):  
M.J. Macera ◽  
R.S. Verma ◽  
R.A. Conte ◽  
M.G. Bialer ◽  
V.R. Klein
Keyword(s):  
Human Chromosome ◽  
Secondary Constriction ◽  
Chromosome 9 ◽  
Positive Band ◽  
Constriction Region

CONSTITUTIVE HETEROCHROMATIN OF INDIAN MUNTJAC CHROMOSOMES REVEALED BY DNASE TREATMENT AND A C-BANDING TECHNIQUE

1974 ◽  
Vol 16 (2) ◽  
pp. 273-280 ◽  
Author(s):  
H. Kato ◽  
K. Tsuchiya ◽  
T. H. Yosida
Keyword(s):  
Secondary Constriction ◽  
Constitutive Heterochromatin ◽  
Banding Technique ◽  
Size Difference ◽  
Indian Muntjac ◽  
C Banding ◽  
Dnase Treatment ◽  
Muntiacus Muntjak ◽  
Secondary Constrictions ◽  
Constriction Region

A karyotype of a female Indian muntjac, Muntiacus muntjak vaginalis, was described. The karyotype was unique in that No. 1 and No. 3 homologous pairs were heteromorphic with respect to the size of their secondary constrictions. In these pairs, one of the homologs always had a longer secondary constriction than that on the corresponding homolog. Heterochromatin in the secondary constriction region was visualized with difficulty by a C-banding technique, but was demonstrated clearly by a DNase treatment followed by Giemsa staining, which also revealed the size difference of the secondary constriction. Centromeric constitutive heterochromatin of No. 1 chromosome was also found to differ in size between the homologs. On the basis of the heteromorphic character of No. 3 chromosome, or an X-autosome complex, it was possible to confirm autoradiographically that X-inactivation had occurred at random.

On an Application of the Metallurgical Stage to Chromosome Morphology

1967 ◽  
Vol 25 ◽  
pp. 28-29
Author(s):  
Godfrey C. Hoskins
Keyword(s):  
Human Chromosome ◽  
Electron Micrographs ◽  
Chromosome Morphology ◽  
Electron Optics ◽  
Electron Micrograph ◽  
Photographic Evidence ◽  
Sophisticated Equipment ◽  
Periodic Arrangement

The first serious electron microscooic studies of chromosomes accompanied by pictures were by I. Elvers in 1941 and 1943. His prodigious study, from the manufacture of micronets to the development of procedures for interpreting electron micrographs has gone all but unnoticed. The application of todays sophisticated equipment confirms many of the findings he gleaned from interpretation of images distorted by the electron optics of that time. In his figure 18 he notes periodic arrangement of pepsin sensitive “prickles” now called secondary fibers. In his figure 66 precise regularity of arrangement of these fibers can be seen. In his figure 22 he reproduces Siegbahn's first stereoscopic electron micrograph of chromosomes.The two stereoscopic pairs of electron micrographs of a human chromosome presented here were taken with a metallurgical stage on a Phillips EM200. These views are interpreted as providing photographic evidence that primary fibers (1°F) about 1,200Å thick are surrounded by secondary fibers (2°F) arranged in regular intervals of about 2,800Å in this metanhase human chromosome. At the telomere the primary fibers bend back on themselves and entwine through the center of each of each chromatid. The secondary fibers are seen to continue to surround primary fibers at telomeres. Thus at telomeres, secondary fibers present a surface not unlike that of the side of the chromosome, and no more susceptible to the addition of broken elements from other chromosomes.

Localization of MODY3 to a 5-cM region of human chromosome 12

Diabetes ◽  
1995 ◽  
Vol 44 (12) ◽  
pp. 1408-1413 ◽  
Author(s):  
S. Menzel ◽  
K. Yamagata ◽  
J. B. Trabb ◽  
J. Nerup ◽  
M. A. Permutt ◽  
...  
Keyword(s):  
Human Chromosome ◽  
Chromosome 12
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