N-Band polymorphism of human acrocentric chromosomes and its relevance to satellite association

1977 ◽  
Vol 36 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Isamu Hayata ◽  
Mitsuo Oshimura ◽  
Avery A. Sandberg
Keyword(s):  
Satellite Association ◽  
Acrocentric Chromosomes

Random single chromatid and nonrandom double chromatid type segregation of human acrocentric chromosomes in BrdU-labeled mitoses

1984 ◽  
Vol 26 (2) ◽  
pp. 137-140 ◽  
Author(s):  
S. Chemitiganti ◽  
R. S. Verma ◽  
S. Ved Brat ◽  
H. Dosik
Keyword(s):  
Human Leukocytes ◽  
Satellite Association ◽  
Chromatid Segregation ◽  
Random Segregation ◽  
Acrocentric Chromosomes ◽  
Single Chromatid ◽  
Cis And Trans

Chromatid segregation was analyzed using satellite association of 5-bromodeoxyuridine (BrdU) differentially stained acrocentric chromosomes of human leukocytes. Data were classified into cis and trans configurations in second and third division cycles. It was found that single chromatid types have random segregation (1:1) while nonrandom segregation was noted for double chromatid types. The nonrandom segregation hypothesis of earlier investigators needs to be reexamined.Key words: chromatid segregation, BrdU, mitosis, acrocentric.

SATELLITE ASSOCIATION IN HUMAN LYMPHOCYTES AND SODIUM CITRATE CONCENTRATION OF HYPOTONIC (SPREADING) SOLUTION

1971 ◽  
Vol 13 (1) ◽  
pp. 115-118 ◽  
Author(s):  
Howard R. Nankin
Keyword(s):  
Sodium Citrate ◽  
Human Lymphocytes ◽  
Satellite Association ◽  
Citrate Concentration ◽  
Acrocentric Chromosomes ◽  
The Relationship

The present investigation examined the relationship between satellite association in lymphocytes and sodium citrate concentration of the hypotonic solutions used to aid in spreading chromosomes. With reduction of sodium citrate from 0.9%, to 0.75%, and to 0.6%, the percentage of acrocentric chromosomes engaged in satellite association went from 32.7%, to 26.8%, and to 19.1% respectively. The reductions appeared to be equally divided between the D group and G group chromosomes.

A role for upstream binding factor in organizing ribosomal gene chromatin

2006 ◽  
Vol 73 ◽  
pp. 77-84 ◽  
Author(s):  
Jane E. Wright ◽  
Christine Mais ◽  
José-Luis Prieto ◽  
Brian McStay
Keyword(s):  
Nucleolar Organizer ◽  
Ribosomal Gene ◽  
Rna Polymerase I ◽  
Nucleolar Organizer Regions ◽  
Binding Factor ◽  
Upstream Binding Factor ◽  
Acrocentric Chromosomes ◽  
Polymerase I ◽  
Secondary Constrictions ◽  
Active Nors

Human ribosomal genes are located in NORs (nucleolar organizer regions) on the short arms of acrocentric chromosomes. During metaphase, previously active NORs appear as prominent chromosomal features termed secondary constrictions, which are achromatic in chromosome banding and positive in silver staining. The architectural RNA polymerase I transcription factor UBF (upstream binding factor) binds extensively across the ribosomal gene repeat throughout the cell cycle. Evidence that UBF underpins NOR structure is provided by an examination of cell lines in which large arrays of a heterologous UBF binding sequences are integrated at ectopic sites on human chromosomes. These arrays efficiently recruit UBF even to sites outside the nucleolus, and during metaphase form novel silver-stainable secondary constrictions, termed pseudo-NORs, that are morphologically similar to NORs.

scholarly journals Molecular Analysis of Nondisjunction in Mice Heterozygous for a Robertsonian Translocation

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1219-1224
Author(s):  
Lara A Underkoffler ◽  
Laura E Mitchell ◽  
A Russell Localio ◽  
Shannon M Marchegiani ◽  
Justin Morabito ◽  
...  
Keyword(s):  
Molecular Analysis ◽  
Robertsonian Translocation ◽  
Metacentric Chromosome ◽  
Paternal Age ◽  
Chromosome 7 ◽  
Parental Origin ◽  
Molecular Genotyping ◽  
Factors Influencing ◽  
Meiotic Nondisjunction ◽  
Acrocentric Chromosomes

Abstract A Robertsonian translocation results in a metacentric chromosome produced by the fusion of two acrocentric chromosomes. Rb heterozygous mice frequently generate aneuploid gametes and embryos, providing a good model for studying meiotic nondisjunction. We intercrossed mice heterozygous for a (7.18) Robertsonian translocation and performed molecular genotyping of 1812 embryos from 364 litters with known parental origin, strain, and age. Nondisjunction events were scored and factors influencing the frequency of nondisjunction involving chromosomes 7 and 18 were examined. We concluded the following: The frequency of nondisjunction among 1784 embryos (3568 meioses) was 15.9%.Nondisjunction events were distributed nonrandomly among progeny. This was inferred from the distribution of the frequency of trisomics and uniparental disomics (UPDs) among all litters.There was no evidence to show an effect of maternal or paternal age on the frequency of nondisjunction.Strain background did not play an appreciable role in nondisjunction frequency.The frequency of nondisjunction for chromosome 18 was significantly higher than that for chromosome 7 in males.The frequency of nondisjunction for chromosome 7 was significantly higher in females than in males. These results show that molecular genotyping provides a valuable tool for understanding factors influencing meiotic nondisjunction in mammals.

CHROMOSOMAL SATELLITE ASSOCIATION

The Lancet ◽  
1967 ◽  
Vol 289 (7489) ◽  
pp. 567
Author(s):  
M.H. Khan ◽  
H. Martin
Keyword(s):  
Satellite Association

Comparative Karyotype Investigations in the European Crayfish Astacus astacus and A. leptodactylus (Decapoda, Astacidae)

Crustaceana ◽  
2011 ◽  
Vol 84 (12-13) ◽  
pp. 1497-1510 ◽  
Author(s):  
M. Pavlica ◽  
M. Mcžić ◽  
G. Klobučar ◽  
M. Šrut ◽  
I. Maguire ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Chromosome Complement ◽  
Size Difference ◽  
45S Rdna ◽  
Astacus Astacus ◽  
Fluorochrome Staining ◽  
Rdna Sites ◽  
Freshwater Habitats ◽  
Acrocentric Chromosomes

AbstractThis study reports on the chromosome number and karyological characteristics of the endangered species of European crayfish, Astacus astacus and A. leptodactylus (Decapoda, Astacidae), both native to Croatian freshwater habitats. The karyotype of A. astacus and A. leptodactylus consists of 2n = 176 and 2n = 180 chromosomes, respectively. The haploid chromosome complement of A. astacus consists of 52 metacentric, 35 metacentric-submetacentric, and 1 acrocentric chromosomes. Fluorochrome staining with 4,6-diamino-2-phenylindole (DAPI) has revealed that the karyotypes of A. astacus and A. leptodactylus are characterized by large heterochromatic blocks located at centromeric and intercalary positions on the chromosomes. Interstitial heterochromatic blocks were more frequent in A. astacus than in A. leptodactylus. In both species pairing of chromosomes in meiosis was regular with the majority of bivalents in a ring- and a dumbbell-form. Fluorescence in situ hybridization (FISH) has revealed that two 45S rDNA loci were present in the investigated species. In A. astacus one of the two 45S rDNA-bearing chromosome pairs was highly heteromorphic, exhibiting a three-fold size difference between 45S rDNA sites on homologous chromosomes. Such a size difference was significantly less pronounced in A. leptodactylus. The karyotype differences between A. astacus and A. leptodactylus suggest changes in chromosome number as well as position of repetitive DNAs have played a role in the karyotype evolution of the species of Astacus.

Karyotype evolution and chromosome numbers in Chrysopsis (Nutt.) Ell. sensu Semple (Compositae–Astereae)

1980 ◽  
Vol 58 (2) ◽  
pp. 164-171 ◽  
Author(s):  
J. C. Semple ◽  
C. C. Chinnappa
Keyword(s):  
Chromosome Numbers ◽  
Karyotype Evolution ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolar Organizer ◽  
Acrocentric Chromosomes

The karyotypes of all species of Chrysopsis were analysed and four basic complements were recognised. The X = 5 karyotype was possessed by all seven n = 5 species and consisted of three submetacentric and two acrocentric chromosomes, one bearing the nucleolar organizer region medially on its short arm. Each X = 4 species had a distinct karyotype. The n = 4 karyotype of C. mariana had diverged less from the X = 5 karyotype than that of C. pilosa. The X2 = 9 karyotype shared by three n = 9 taxa was found to be little more than a combination of the X = 5 karyotype and the X = 4 mariana karyotype and was therefore of allopolyploid origin. Some shifting in the location of the nucleolar organizer region has occurred in each group.

scholarly journals Jumping Translocations of 1q in Myelodysplastic Syndrome and Acute Myeloid Leukemia: Report of Three Cases and Review of Literature

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
T. Couture ◽  
K. Amato ◽  
A. DiAdamo ◽  
P. Li
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
De Novo ◽  
Pericentromeric Region ◽  
Review Of Literature ◽  
Cell Lineages ◽  
Chromosome 1Q ◽  
Acrocentric Chromosomes ◽  
Acute Myeloid

Jumping translocations of 1q refer to the break-off of chromosome 1q as a donor fusing to two or more recipient chromosomes. We detected jumping translocations of 1q in three patients with initial diagnosis of myelodysplastic syndrome (MDS) and later progression to acute myeloid leukemia (AML). Review of literature found jumping translocations of 1q in 30 reported cases of MDS and AML. The cytogenetic findings from these 33 cases showed that seven cases had a stemline clone and 26 cases had de novo jumping translocations of 1q in which 5% of cell lineages had additional structural rearrangements. In 75% of cases, the 1q donor jumped to the short arm of recipient acrocentric chromosomes. Approximately 82% of the fusions occurred in the telomeric regions of short and long arms and 18% occurred in the pericentric or interstitial regions of recipient chromosomes. Hypomethylation of the donor 1q pericentromeric region and shortened telomeres in recipient chromosomes were associated with the formation of jumping translocations. Jumping translocations of 1q as an indication of chromosomal instability pose high risk for progression of MDS to AML and a poor prognosis. Further understanding of underlying genomic defects and their clinical significance will improve overall treatment and patient care.

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