Analysis of the morphology of short arms of human acrocentric chromosomes by sequential staining for G and C banding

In this work, Bunocephalus doriae was cytogenetically analyzed. A karyotype with a diploid number of 2n= 50 comprising 6m, 10sm, 6st, and 28a (FN= 72) chromosomes was observed. The occurrence of an asymmetric karyotype with a large number of acrocentric chromosomes distinguishes this species from others the Order Siluriformes. An exclusive character observed is the first pair of subtelocentric as the largest chromosome pair of the complement. NORs detected using AgNO3 were located in the terminal regions, on the short arm of a subtelocentric chromosome pair (pair 11), in a secondary constriction. C-banding revealed heterochromatic centromeric regions on several chromosomes of the complement after C-banding. This is the first cytogenetic description of this species and the first cytogenetic report on a member of the family Aspredinidae.

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First chromosome data on Steindachneridion doceanum (Siluriformes: Pimelodidae): a critically endangered catfish endemic of the Doce River basin, Brazil

Neotropical Ichthyology ◽

10.1590/1982-0224-20180066 ◽

2018 ◽

Vol 16 (4) ◽

Cited By ~ 1

Author(s):

Ana Claudia Swarça ◽

Mário Luis Orsi ◽

Fábio Hiroshi Takagui ◽

Ana Lucia Dias ◽

Jorge Abdala Dergam ◽

...

Keyword(s):

Secondary Constriction ◽

Extinction Risk ◽

Present Report ◽

5S Rdna ◽

Rdna Genes ◽

C Banding ◽

Endemic Taxon ◽

Acrocentric Chromosomes ◽

Doce River ◽

Submetacentric Pair

ABSTRACT The present report represents the first cytogenetic description of Steindachneridion doceanum, great catfish which is currently at high extinction risk and it is listed as threatened on the red list of the Brazilian Ministry of the Environment, also are suggested karyotype relationships with other species of the same genus endemic from other river basins. The results revealed a diploid number of 2n = 56 and the karyotype composed of 18 metacentric, 20 submetacentric, 10 subtelocentric and 8 acrocentric chromosomes (NF = 104). The AgNORs and CMA3 signals were coincident in location occupying the short arm of an acrocentric chromosome pair (25th), in a secondary constriction. The 5S rDNA genes were localized on the short arms of one subtelocentric pair. C-banding revealed terminal blocks on the short arms on many chromosomes as well as terminal positive bands at the both ends of a submetacentric pair. C banding also revealed a large heterochromatic block in the secondary constriction (25th) region that was coincident with the AgNORs sites and CMA3+ bright bands. In spite S. doceanum represent an endemic taxon, in spite their geographic isolation their cytogenetic characteristics show similarities with other species of the genus.

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Karyotype, C-band and NOR phenotype of Anatolian endemic fish Squalius anatolicus (Bogutskaya, 1997) (Teleostei, Leuciscidae)

Ege Journal of Fisheries and Aquatic Sciences ◽

10.12714/egejfas.38.3.07 ◽

2021 ◽

Vol 38 (3) ◽

pp. 311-315

Author(s):

Sevgi Ünal Karakuş ◽

Muhammet Gaffaroğlu

Keyword(s):

Chromosome Pair ◽

Constitutive Heterochromatin ◽

Nucleolus Organizer ◽

Submetacentric Chromosome ◽

Nucleolus Organizer Regions ◽

C Banding ◽

Nor Phenotype ◽

Acrocentric Chromosomes ◽

Endemic Fish ◽

Lake Beysehir

The karyotype and distribution of constitutive heterochromatin and nucleolus organizer regions (NORs) of Anatolian leuciscine endemic to Lake Beysehir, Squalius anatolicus (Bogutskaya, 1997) were analyzed respectively using conventional Giemsa-staining, C-banding and Ag-impregnation. Diploid chromosome number was 2n = 50 and karyotype consisted of 7 pairs of metacentric, 13 pairs of submetacentric, 5 pairs of subtelo- to acrocentric chromosomes, NF value equaled 90. Heteromorphic elements indicating sex chromosomes were not detected. C-banding revealed clear pericentromeric constitutive heterochromatin blocks in several chromosomes. Ag-impregnation revealed the size heteromorphism of NORs that covered almost the entire short arms of the middle-sized submetacentric chromosome pair. The karyotype pattern and simple NOR phenotype of S. anatolicus are nearly identical with that found not only in Squalius species analyzed to date but also in many other representatives of the Eurasian leuciscine cyprinids, which indicates remarkable chromosome stasis in this leuciscid lineage.

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IDENTIFICATION OF THE SEX CHROMOSOMES IN THE BALD EAGLE

Canadian Journal of Genetics and Cytology ◽

10.1139/g75-025 ◽

1975 ◽

Vol 17 (2) ◽

pp. 187-191 ◽

Cited By ~ 12

Author(s):

W. Au ◽

N. S. Fechheimer ◽

S. Soukup

Keyword(s):

Sex Chromosomes ◽

Bald Eagle ◽

Haliaeetus Leucocephalus ◽

W Chromosome ◽

Bald Eagles ◽

C Banding ◽

Size Groups ◽

Acrocentric Chromosomes

Karyotypes of five American bald eagles (Haliaeetus leucocephalus and H. alacanus) are compared. All had 2n = 66 chromosomes which fell into 3 size groups: A, 20 pairs of biarmed chromosomes; B, 9 pairs of acrocentric chromosomes and C, 4 pairs of microchromosomes. C-banding was done in two eagles and a heterochromatic W chromosome was identified in a presumptive female. The ZZ and ZW chromosomes could be identified in the karyotypes.

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

Canadian Journal of Genetics and Cytology ◽

10.1139/g73-089 ◽

1973 ◽

Vol 15 (4) ◽

pp. 757-761 ◽

Cited By ~ 2

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.

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Cytotaxonomy, heterochromatic polymorphism and natural triploidy of a species of Astyanax (Pisces, Characidae) endemic to the Iguaçu river basin

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132007000100008 ◽

2007 ◽

Vol 50 (1) ◽

pp. 67-74 ◽

Cited By ~ 17

Author(s):

Daniel Luis Zanella Kantek ◽

Rafael Bueno Noleto ◽

Alberto Sérgio Fenocchio ◽

Marta Margarete Cestari

Keyword(s):

River Basin ◽

Restriction Enzyme ◽

Cytogenetic Analysis ◽

C Banding ◽

Acrocentric Chromosomes ◽

Clear Differentiation ◽

Paracentric Inversions ◽

Iguaçu River

Cytogenetic analysis with Astyanax sp. D revealed a karyotype of 2n=50 with 2M+26SM+6ST+16A, besides a triploid specimen showing 2n=75 chromosomes (3M+39SM+9ST+24A). C-banding strongly stained the terminal regions of several SM-ST-A chromossomes. Two pairs of acrocentric chromosomes presented interstitial heterochromatin, this state being polymorphic and occuring due to possible paracentric inversions. The results obtained with the AluI restriction enzyme and A3 chromomycin were similar to the C-banding. Relationships were proposed between Astyanax sp. D and A. scabripinnis, as well as considerations for a possible origin of the triploid specimen (2n=3x=75). When comparing the present results with cytogenetic features of other endemic Astyanax species in the Iguaçu river (A. sp. B and C), a clear differentiation was observed between them, indicating cytogenetics as an important cytotaxonomic tool.

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A role for upstream binding factor in organizing ribosomal gene chromatin

Biochemical Society Symposium ◽

10.1042/bss0730077 ◽

2006 ◽

Vol 73 ◽

pp. 77-84 ◽

Cited By ~ 14

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.

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