Heterochromatin organization in the nucleus of Indian muntjac (Muntiacus muntjak)

1986 ◽  
Vol 28 (4) ◽  
pp. 628-630 ◽  
Author(s):  
Ram S. Verma ◽  
Jessey P. Jacob ◽  
Arvind Babu
Keyword(s):  
Restriction Endonuclease ◽  
Y Chromosome ◽  
X Chromosome ◽  
General Pattern ◽  
Banding Technique ◽  
Chromosome Y ◽  
Heterochromatic Segment ◽  
Indian Muntjac ◽  
Muntiacus Muntjak

The heterochromatin in Indian muntjac (Muntiacus muntjak) is located at the periphery of primary constrictions of all the chromosomes. The X chromosome contains significantly larger amounts of heterochromatin than the rest of the complement by C-banding technique. However, the small portion of C-band region was found to be resistant by restriction endonuclease HaeIII (5′… GG ↓ CC … 3′) and was clearly visible on the nucleus. Therefore, the position of this large heterochromatic segment is examined at somatic metaphases. The distribution of the heterochromatin of the X chromosome observed in Indian muntjac is contrary to the general pattern observed in other species, i.e., the chromosomes consisting greater amount of heterochromatin are located more peripherally than those with lesser amount. However, the smaller Y chromosome (Y1) is frequently found at the periphery. The present findings suggest that the role of heterochromatin organization in the nucleus vary between different heterochromatic segments of the same species and vary from species to species.Key words: heterochromatin, chromosome, nucleus, metaphase, Muntiacus muntjak.

scholarly journals Chromosome Y Isodicentrics in two Cases with Ambiguous genitalia and Features of Turner Syndrome

2008 ◽  
Vol 11 (2) ◽  
pp. 51-58
Author(s):  
A Lungeanu ◽  
A Arghir ◽  
S Arps ◽  
G Cardos ◽  
N Dumitriu ◽  
...  
Keyword(s):  
Turner Syndrome ◽  
Y Chromosome ◽  
Ambiguous Genitalia ◽  
Peripheral Blood Lymphocytes ◽  
Chromosome Y ◽  
Y Chromosomes ◽  
New Information ◽  
Pathway Perturbation

Chromosome Y Isodicentrics in two Cases with Ambiguous genitalia and Features of Turner SyndromeKaryotype investigations using classical cytogenetics, fluorescencein situhybridization (FISH) and polymerase chain reaction (PCR) techniques were used for the characterization of Y chromosome structural anomalies found in two patients with ambiguous genitalia and features of Turner syndrome. Both exhibited mosaic karyotypes of peripheral blood lymphocytes. The karyotype was 45, X[90]/ 46, X, idic(Y)(p11.3).ish idic(Y) (wcpY+, DXYS130++,SRY++,DYZ3++,DYZ1++, DYS224++)[10] in one case, and the karyotype was 45, X[65]/46, X, idic(Y) (q11).ish idic(Y)(SRY++, RP11-140H23-)[35] in the other case. Derivative Y chromosomes were different in shape and size and positive for the SRY gene, a common underlying element of ambiguous genitalia phenotypes. These results add new information concerning the role of Y chromosome structural abnormalities in sex determination pathway perturbation which are poorly understood, and highlight the importance of the sex chromosomes integrity for a normal sex phenotype development.

Observations on the So-Called Sex Chromatin in Man

1957 ◽  
Vol 6 (3) ◽  
pp. 393-402 ◽  
Author(s):  
Juhan Reitalu
Keyword(s):  
Nuclear Structure ◽  
Y Chromosome ◽  
X Chromosome ◽  
Liver Tissue ◽  
Male And Female ◽  
Heterochromatic Segment ◽  
Sex Chromatin ◽  
The Difference ◽  
Diploid Cells

SUMMARYThe difference in nuclear structure between male and female tissues in man has been examined in liver tissue from three embryos of each sex. The so-called sex chromatin consists of a large heterochromatic segment of the X chromosome, thus existing in duplicate in female diploid cells. The two segments have a tendency of juxtaposition resulting in a larger heterochromatic body in female than in male cells. Beside the large heterochromatic segment the X chromosome has, in the tissues studied, a euchromatic segment attached through a small terminal heterochromatic knob to a nucleolus. In male cells the euchromatic segment of the X chromosome is often joined terminally to a small heterochromatic segment believed to belong to the Y chromosome.

The Role of Genetic Mutations in Y Chromosome Infertility Syndrome

2020 ◽  
pp. 1-6
Author(s):  
Shahin Asadi
Keyword(s):  
Y Chromosome ◽  
Sperm Cell ◽  
Sex Chromosome ◽  
Genetic Disorder ◽  
Genetic Material ◽  
Genetic Mutations ◽  
Sperm Cells ◽  
Sperm Production ◽  
Chromosome Y

Sex chromosome Y infertility is a genetic disorder that affects sperm production and causes affected men to become infertile. Most men with Y chromosome infertility syndrome have some sperm cells in their urine that can be extracted for this purpose. As the name implies, this type of infertility is caused by changes in the Y sex chromosome. Infertility of the Y sex chromosome is usually caused by the removal of genetic material in areas of the Y chromosome called Azosperm Factor (AZF) A, B or C. Keywords: Azosperm Factor; Oligospermia, Sperm Cell: Sex chromosome Y infertility

scholarly journals First Report on Karyotypic, Morphometric and Meiotic Analysis of a Predatory Bombardier Beetle Pherosophus catoirai (Coleoptera: Carabidae) from Jammu region of Outer Himalayas, India

2021 ◽  
Vol 18 (4) ◽  
pp. 817-822
Author(s):  
Arshad Ayoub Bhatti ◽  
Nidhi Slathia ◽  
Manvi K
Keyword(s):  
Chromosome Number ◽  
Y Chromosome ◽  
X Chromosome ◽  
Chromosome Complement ◽  
Diploid Chromosome Number ◽  
Meiotic Analysis ◽  
Chromosome Y ◽  
First Report ◽  
Metaphase Stage ◽  
Spermatogonial Metaphase

Chromosomal studies and manual karyotyping are the aged techniques for determining the identity of a species on evolutionary scale; however, these techniques are simple, reliable and inexpensive to authenticate the existence of a particular species. In the present work, the chromosome complement and meiotic processes of a predatory bombardier beetle Pherosophus catoirai were investigated. This species presented 2n=35 as diploid chromosome number and the chromosomal formula was found to be 12m+8sm+12st+X0. Sex mechanism was X0 type with metacentric X chromosome. Y chromosome was absent in this species. Karyotype revealed small chromosomes except X chromosome which is found to be largest in the spermatogonial metaphase stage. Meiotic stages were pachytene, diplotene, diakinesis and metaphase-I. Present study may find importance to analyse evolution of chromosomes in order Coleoptera particularly in family Carabidae.

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.

scholarly journals DNA Environment of Centromeres and Non-Homologous Chromosomes Interactions in Mouse

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3375
Author(s):  
Victor Spangenberg ◽  
Mikhail Losev ◽  
Ilya Volkhin ◽  
Svetlana Smirnova ◽  
Pavel Nikitin ◽  
...  
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Satellite Dna ◽  
Centromeric Region ◽  
Autosomal Bivalents ◽  
Homologous Chromosomes ◽  
Interdisciplinary Knowledge ◽  
Eukaryotic Genomes

Although the pericentromeric regions of chromosomes that are enriched in tandemly repeated satellite DNA represent a significant part of eukaryotic genomes, they remain understudied, which is mainly due to interdisciplinary knowledge gaps. Recent studies suggest their important role in genome regulation, karyotype stability, and evolution. Thus, the idea of satellite DNA as a junk part of the genome has been refuted. The integration of data regarding molecular composition, chromosome behaviour, and the details of the in situ organization of pericentromeric regions is of great interest. The objective of this work was a cytogenetic analysis of the interactions between pericentromeric regions from non-homologous chromosomes in mouse spermatocytes using immuno-FISH. We analysed two events: the associations between centromeric regions of the X chromosome and autosomes and the associations between the centromeric regions of the autosomal bivalents that form chromocenters. We concluded that the X chromosome forms temporary synaptic associations with different autosomes in early meiotic prophase I, which can normally be found until the pachytene–diplotene, without signs of pachytene arrest. These associations are formed between the satellite-DNA-rich centromeric regions of the X chromosome and different autosomes but do not involve the satellite-DNA-poor centromeric region of the Y chromosome. We suggest the hypothetical model of X chromosome competitive replacement from such associations during synaptic correction. We showed that the centromeric region of the X chromosome in association remains free of γH2Ax-dependent chromatin inactivation, while the Y chromosome is completely inactivated. This finding highlights the predominant role of associations between satellite DNA-rich regions of different chromosomes, including the X chromosome. We suppose that X-autosomal transient associations are a manifestation of an additional synaptic disorder checkpoint. These associations are normally corrected before the late diplotene stage. We revealed that the intense spreading conditions that were applied to the spermatocyte I nuclei did not lead to the destruction of stretched chromatin fibers of elongated chromocenters enriched in satellite DNA. The tight associations that we revealed between the pericentromeric regions of different autosomal bivalents and the X chromosome may represent the basis for a mechanism for maintaining the repeats stability in the autosomes and in the X chromosome. The consequences of our findings are discussed.

X-4 Translocations and Meiotic Drive in Drosophila melanogaster Males: Role of Sex Chromosome Pairing

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 409-413
Author(s):  
Bruce McKee
Keyword(s):  
Drosophila Melanogaster ◽  
Y Chromosome ◽  
X Chromosome ◽  
Chromosome Pairing ◽  
Sex Chromosome ◽  
Meiotic Drive ◽  
Meiotic Pairing ◽  
Size Dependent ◽  
Chromosome Breakpoint

ABSTRACT Males carrying certain X-4 translocations exhibit strongly skewed sperm recovery ratios. The XP4D half of the translocation disjoins regularly from the Y chromosome and the 4PXD half disjoins regularly from the normal 4. Yet the smaller member of each bivalent is recovered in excess of its pairing partner, apparently due to differential gametic lethality. Chromosome recovery probabilities are multiplicative; the viability of each genotype is the product of the recovery probability of its component chromosomes. Meiotic drive can also be caused by deficiency for X heterochromatin. In(1)sc4Lsc8R males show the same size dependent chromosome recoveries and multiplicative recovery probabilities found in T(1;4)BS males. Meiotic drive in In(1)sc4Lsc8R males has been shown to be due to X-Y pairing failure. Although pairing is regular in the T(X;4) males, the striking phenotypic parallels suggest a common explanation. The experiments described below show that the two phenomena are, in fact, one and the same. X-4 translocations are shown to have the same effect on recovery of independently assorting chromosomes as does In(1)sc4Lsc8R. Addition of pairing sites to the 4PXD half of the translocation eliminates drive. A common explanation—failure of the distal euchromatic portion of the X chromosome to participate in X:Y meiotic pairing—is suggested as the cause for drive. The effect of X chromosome breakpoint on X-4 translocation induced meiotic drive is investigated. It is found that translocations with breakpoints distal to 13C on the salivary map do not cause drive while translocations broken proximal to 13C cause drive. The level of drive is related to the position of the breakpoint—the more proximal the breakpoint the greater the drive.

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