LATERAL SUBUNITS IN C-BANDS OF UNREPLICATED CHROMOSOMES OF DISSOSTEIRA CAROLINA (L.) (ORTHOPTERA:ACRIDIDAE)

1973 ◽  
Vol 15 (4) ◽  
pp. 757-761 ◽  
Author(s):  
A. A. Bregman
Keyword(s):  
Banding Pattern ◽  
Centromeric Region ◽  
Telomeric Region ◽  
Mitotic Chromosomes ◽  
Dual Structure ◽  
C Banding ◽  
Meiotic Chromosomes ◽  
Acrocentric Chromosomes

The C-banding pattern is described for the chromosomes of the grasshopper Dissosteira Carolina (2n♂ = 24, ♀ = 23; XX-XO). Each of the 24 acrocentric chromosomes has a prominent C-band at the centromeric region and most chromosomes have a less prominent C-band at the distal telomeric region. Usually, one or more pairs of chromosomes has a C-band in the short arm. The C-band at the centromeric region appears to be composed of two lateral subunits in unreplicated meiotic chromosomes at anaphase II and telophase II in a number of secondary spermatocytes and in unreplicated mitotic chromosomes at anaphase in several spermatogonia. The C-band at the distal telomeric region appears similarly divided in unreplicated chromatids at anaphase I and metaphase II in several spermatocytes. The lateral subunits may be an artifact or may reflect the presence of a dual structure at C-banded regions.

Karyotype and C-banding pattern of mitotic chromosomes in alfalfa, Medicago sativa L.

1995 ◽  
Vol 114 (5) ◽  
pp. 451-453 ◽  
Author(s):  
E. Falistocco ◽  
M. Falcinelli ◽  
F. Veronesi
Keyword(s):  
Medicago Sativa ◽  
Banding Pattern ◽  
Mitotic Chromosomes ◽  
C Banding ◽  
Medicago Sativa L

Fluorescence banding in mitotic and meiotic chromosomes of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae)

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 580-588 ◽  
Author(s):  
D. G. Bedo
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Silver Staining ◽  
Ceratitis Capitata ◽  
Fruit Fly ◽  
Mediterranean Fruit Fly ◽  
Mitotic Chromosomes ◽  
C Banding ◽  
Meiotic Chromosomes ◽  
The Mediterranean

Mitotic and meiotic chromosomes of the Mediterranean fruit fly, Ceratitis capitata, were studied using three counterstain-enhanced fluorescence staining methods. The tristaining technique allowed chromomycin A3 (CMA) and distamycin – diamidinophenylindole (DA–DAPI) fluorescence to be observed on the same chromosomes. DAPI–actinomycin D (DAPI–AMD) fluorescence was also carried out. These techniques were complemented with quinacrine staining and C-banding. The results were compared with earlier data on silver staining. The sex chromosomes, particularly the X chromosome, show great banding detail with extensive longitudinal differentiation in mitotic chromosomes. GC- and AT-specific fluorescence is not found in the expected reciprocal pattern at all sites. Comparison with C-banding and silver staining shows that intense fluorescence occurs in lightly C banded regions and silver bands correspond to fluorescent bands rather than nucleolar organizers. The combination of staining data suggests that much of the X chromosome has characteristics intermediate between heterochromatin and euchromatin. Meiotic X chromosomes show much less detail and reduced fluorescence intensity but can still be easily traced throughout meiosis and spermatogenesis.Key words: fluorescence banding, sex chromosomes, Mediterranean fruit fly, Ceratitis capitata.

Chromosomes of the Parasitic Isopod Anilocra Physodes

Crustaceana ◽  
1996 ◽  
Vol 69 (1) ◽  
pp. 56-62
Author(s):  
Maria Stella Colomba ◽  
Roberto Vitturi ◽  
Lorenzo Pellerito ◽  
Eliodoro Catalano
Keyword(s):  
Chromosome Number ◽  
Diploid Number ◽  
Centromeric Region ◽  
Banding Technique ◽  
Robertsonian Fusion ◽  
Mitotic Chromosomes ◽  
C Banding ◽  
Parasitic Isopod

AbstractCounts of mitotic chromosomes have allowed to determine 2n = 12 as the modal diploid number of Anilocra physodes. Application of the C-banding technique reveals that two hetero-chromatic blocks bordering the centromeric region occur in each chromosome. This supports the notion that the actual low chromosome number of A. physodes may have been derived through a process of Robertsonian fusion.

Cytogenetic analysis of some Brazilian marsupials (Didelphidae: Marsupialia)

1986 ◽  
Vol 28 (1) ◽  
pp. 21-29 ◽  
Author(s):  
C. Casartelli ◽  
S. R. Rogatto ◽  
I. Ferrari
Keyword(s):  
X Chromosome ◽  
Centromeric Region ◽  
Nucleolar Organizer ◽  
The Other ◽  
Nucleolar Organizer Regions ◽  
Telomeric Region ◽  
Submetacentric Chromosome ◽  
Negative Band ◽  
Acrocentric Chromosomes ◽  
Didelphis Albiventris

Three species of marsupials from the Amazon region (Marmosa cinerea, Caluromys lanatus, and Didelphis marsupialis) and two from the region of São Paulo (Didelphis marsupialis and Didelphis albiventris) were studied. The G-banding pattern of the species with 2n = 14 (M. cinerea and C. lanatus) was very similar, as well as the pattern of G-bands in the species with 22 chromosomes (Didelphis). All of the autosomes of M. cinerea and D. albiventris have centromeric C-bands and the Y chromosome is totally C-band positive. The long arm of the M. cinerea X chromosome is completely C-band positive except for a negative band close to the centromeric region. In D. albiventris the long arm of the X chromosome is C-band positive except for a negative band close to the telomeric region. In M. cinerea the silver-stained nucleolar organizer regions (Ag-NORs) are found in the acrocentric chromosomes, being located in the telomeric region of one pair and in the centromeric region of the other pair. Caluromys lanatus has centromeric Ag-NORs in one acrocentric and in one submetacentric chromosome pairs. Didelphis marsupialis has three chromosome pairs with telomeric Ag-NORs. In D. albiventris the Ag-NORs are terminal and located in both arms of one pair and in the long arm of two pairs of chromosomes.Key words: cytogenetics, marsupials, chromosomes.

Heterochromatin Distribution in the Chromosome Complement of Triturus boscai (Amphibia: Caudata: Salamandridae)

1982 ◽  
Vol 3 (4) ◽  
pp. 309-315 ◽  
Author(s):  
Pilar Herrero
Keyword(s):  
Banding Pattern ◽  
Related Species ◽  
Chromosome Complement ◽  
Black Spot ◽  
Gastric Tissue ◽  
Centromere Region ◽  
Mitotic Chromosomes ◽  
C Banding ◽  
Small Black Spot

AbstractThe C-banding pattern of the I berian endemism Triturus boscai has been analyzed using mitotic chromosomes from gastric tissue and testes. The chromosome pairs are characterized for presenting a small black spot on their centromeres although a pair of pericentric bands are placed on both sides of the centromere region. Some chromosomes are characterized by the presence of terminal and subterminal bands. Present results are compared with those referred to related species within the group Triturus.

Cytological characterisation of heterochromatin in mitotic and meiotic chromosomes of the Old World screwworm fly, Chrysomya bezziana (Diptera: Calliphoridae)

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 631-637 ◽  
Author(s):  
D. G. Bedo
Keyword(s):  
Sex Chromosomes ◽  
Mitotic Chromosomes ◽  
Old World ◽  
Screwworm Fly ◽  
C Banding ◽  
Meiotic Chromosomes ◽  
Bright Fluorescence ◽  
Y Chromosomes ◽  
Background Staining ◽  
Chrysomya Bezziana

Mitotic and meiotic chromosomes of the Old World screwworm fly, Chrysomya bezziana, were studied using C-banding and quinacrine and counterstain-enhanced fluorescence techniques. The five autosomes in the karyotype are evenly graded in size, with somewhat variable arm ratios. Distinguishing all autosomes on these features alone can be difficult. C-banding produces small centromeric bands in the autosomes, whereas the much longer X and Y chromosomes have extensive dark C-band blocks with intermediate background staining. Most bright fluorescence occurs in the sex chromosomes, particularly the X chromosome, which has remarkable banding detail. Band resolution is greatly increased in mitotic metaphase cells from embryos. Quinacrine staining of mitotic chromosomes produces bright fluorescence at the centromere regions of chromosomes 2, 3, and 4, assisting in their identification. Meiotic chromosomes have distinctly reduced brightness and resolution of fluorescent bands and show marked chromatid asynapsis in the brighter regions of the sex chromosomes. Fluorochromes staining A∙T-rich DNA (quanacrine and 4,6-diamidino-2-phenylindole (DAPI)) produce bright staining in a large proportion of the sex chromosomes. By contrast chromomycin, which binds preferentially to G∙C-rich DNA, stains a much smaller proportion of the sex chromosomes than expected from reciprocal staining. Together with the asynapsis data this indicates that much of the heterochromatin in the sex chromosomes has unusual structural properties.Key words: Chrysomya bezziana, screwworm, karyotype, C-banding, fluorescence, heterochromatin.

scholarly journals Analysis of the Functions of Recombination-Related Genes in the Generation of Large Chromosomal Deletions by Loop-Out Recombination in Aspergillus oryzae

2012 ◽  
Vol 11 (4) ◽  
pp. 507-517 ◽  
Author(s):  
Tadashi Takahashi ◽  
Masahiro Ogawa ◽  
Yasuji Koyama
Keyword(s):  
Aspergillus Oryzae ◽  
Chromosomal Region ◽  
Centromeric Region ◽  
Chromosome 8 ◽  
Telomeric Region ◽  
Dna Double Strand Breaks ◽  
Chromosomal Structure ◽  
Content Type ◽  
Strand Breaks ◽  
Chromosomal Deletions

ABSTRACT Loop-out-type recombination is a type of intrachromosomal recombination followed by the excision of a chromosomal region. The detailed mechanism underlying this recombination and the genes involved in loop-out recombination remain unknown. In the present study, we investigated the functions of ku70 , ligD , rad52 , rad54 , and rdh54 in the construction of large chromosomal deletions via loop-out recombination and the effect of the position of the targeted chromosomal region on the efficiency of loop-out recombination in Aspergillus oryzae . The efficiency of generation of large chromosomal deletions in the near-telomeric region of chromosome 3, including the aflatoxin gene cluster, was compared with that in the near-centromeric region of chromosome 8, including the tannase gene. In the Δ ku70 and Δ ku70-rdh54 strains, only precise loop-out recombination occurred in the near-telomeric region. In contrast, in the Δ ligD , Δ ku70-rad52 , and Δ ku70-rad54 strains, unintended chromosomal deletions by illegitimate loop-out recombination occurred in the near-telomeric region. In addition, large chromosomal deletions via loop-out recombination were efficiently achieved in the near-telomeric region, but barely achieved in the near-centromeric region, in the Δ ku70 strain. Induction of DNA double-strand breaks by I-SceI endonuclease facilitated large chromosomal deletions in the near-centromeric region. These results indicate that ligD , rad52 , and rad54 play a role in the generation of large chromosomal deletions via precise loop-out-type recombination in the near-telomeric region and that loop-out recombination between distant sites is restricted in the near-centromeric region by chromosomal structure.

The influence of fixation on the morphology of mitotic chromosomes

1986 ◽  
Vol 28 (4) ◽  
pp. 536-539 ◽  
Author(s):  
Axel J. J. Dietrich
Keyword(s):  
Acetic Acid ◽  
Chemical Composition ◽  
Strong Influence ◽  
Chromosome Structure ◽  
Human Lymphocytes ◽  
Chromosome Morphology ◽  
Mitotic Chromosomes ◽  
Specific Chemical ◽  
C Banding ◽  
Sister Chromatids

It is well known that there is a strong influence of fixation, i.e., acetic methanol versus formaldehyde, on the chromosome morphology at stages of the first meiotic division. In this study the influence of both these types of fixation on the morphology of mitotic chromosomes was examined in human lymphocytes. After methanol – acetic acid (3:1) fixation, the chromosomes show the "classical" condensed shape in which it is not always possible to recognize the two sister chromatids. These chromosomes are accessible to the conventional G-, R-, and C-banding techniques. After formaldehyde fixation at a relatively high pH, the chromosomes are thinner and longer (two to six times) when compared with chromosomes following methanol – acetic acid fixation. They show a scaffold-like morphology, sometimes with a halo of thin material around it. In all cases the two sister chromatids could be recognized. This chromosome structure could be easily stained with silver, Giemsa, 4,6-diamino-2-phenyl-indole (DAPI), and fluorescein isocyanate isomere 1 (FITC). The results obtained following these stainings gave no indication to any specific chemical composition of a probable central scaffold. The scaffold-like structures were not accessible to G-, R-, or C-banding techniques. The only effect observed following these banding techniques was the disappearance of the halo of thin material around the central scaffold-like structure.Key words: chromosome structure, fixation influence, human lymphocytes.

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