scholarly journals Cytogenetical studies on the Japanese raccoon dog. IV. Robertsonian fission of three chromosome pairs, nos. 5,8, and 11, found in a specimen collected from Kanagawa-ken, with regard to the numerical variation of B-chromosomes.

1984 ◽  
Vol 60 (8) ◽  
pp. 293-296 ◽  
Author(s):  
Tosihide H. YOSIDA ◽  
Masayasu Y. WADA
Keyword(s):  
B Chromosomes ◽  
Raccoon Dog ◽  
Numerical Variation

scholarly journals Sequencing of Supernumerary Chromosomes of Red Fox and Raccoon Dog Confirms a Non-Random Gene Acquisition by B Chromosomes

Genes ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 405 ◽  
Author(s):  
Alexey Makunin ◽  
Svetlana Romanenko ◽  
Violetta Beklemisheva ◽  
Polina Perelman ◽  
Anna Druzhkova ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Red Fox ◽  
B Chromosome ◽  
Mendelian Inheritance ◽  
B Chromosomes ◽  
Nyctereutes Procyonoides ◽  
Segmental Duplications ◽  
Raccoon Dog ◽  
Gene Acquisition ◽  
Genomic Regions

B chromosomes (Bs) represent a variable addition to the main karyotype in some lineages of animals and plants. Bs accumulate through non-Mendelian inheritance and become widespread in populations. Despite the presence of multiple genes, most Bs lack specific phenotypic effects, although their influence on host genome epigenetic status and gene expression are recorded. Previously, using sequencing of isolated Bs of ruminants and rodents, we demonstrated that Bs originate as segmental duplications of specific genomic regions, and subsequently experience pseudogenization and repeat accumulation. Here, we used a similar approach to characterize Bs of the red fox (Vulpes vulpes L.) and the Chinese raccoon dog (Nyctereutes procyonoides procyonoides Gray). We confirm the previous findings of the KIT gene on Bs of both species, but demostrate an independent origin of Bs in these species, with two reused regions. Comparison of gene ensembles in Bs of canids, ruminants, and rodents once again indicates enrichment with cell-cycle genes, development-related genes, and genes functioning in the neuron synapse. The presence of B-chromosomal copies of genes involved in cell-cycle regulation and tissue differentiation may indicate importance of these genes for B chromosome establishment.

Karyotype, C-banding, chromosomal location of active nucleolar organizing regions, and B-chromosomes in Lasius niger (Hymenoptera, Formicidae)

Genome ◽  
1990 ◽  
Vol 33 (2) ◽  
pp. 267-272 ◽  
Author(s):  
T. Palomeque ◽  
E. Chica ◽  
R. Díaz de la Guardia
Keyword(s):  
Germ Cells ◽  
Chromosomal Location ◽  
Ganglion Cells ◽  
Cerebral Ganglion ◽  
B Chromosomes ◽  
Lasius Niger ◽  
Nucleolar Organizing Regions ◽  
Nucleolar Organizing Region ◽  
C Banding ◽  
Numerical Variation

The karyotype of Lasius niger (n = 15) was analysed using C-banding and observation of nucleolar organizing region (NOR) sites. C-banding showed the existence of heterochromatin in the paracentromeric regions of all chromosomes. Two sites with primary NORs were found in chromosomes 6 and 8. Chromosome 13 showed a secondary NOR. In both cases, the NORs were located in the paracentromeric region. B-chromosomes were found in male and female germ cells. They exhibited intra- and inter-individual numerical variation. No B-chromosomes were observed in somatic cells (cerebral ganglion cells) of all castes. The Bs are telocentric, small, and clearly distinguishable from the regular members of the complement. They show positive heteropycnosis in meiotic prophase and they are highly C-band positive. The activity of NORs does not change when Bs are present. Several aspects of the behaviour of these Bs are examined.Key words: C-bands, nucleolar organizing region (primary), nucleolar oganizing region (secondary), B-chromosomes, Formicidae.

Three-Dimensional Positioning of B Chromosomes in Fibroblast Nuclei of the Red Fox and the Chinese Raccoon Dog

2013 ◽  
Vol 139 (4) ◽  
pp. 243-249 ◽  
Author(s):  
B. Kociucka ◽  
J. Sosnowski ◽  
A. Kubiak ◽  
A. Nowak ◽  
P. Pawlak ◽  
...  
Keyword(s):  
Red Fox ◽  
Three Dimensional ◽  
B Chromosomes ◽  
Raccoon Dog

Polysomy and supernumerary chromosomes in Ornithogalum umbellatum L. (Liliaceae)

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 19-25 ◽  
Author(s):  
C. Ruiz Rejón ◽  
R. Lozano ◽  
M. Ruiz Rejón
Keyword(s):  
Key Words ◽  
Natural Population ◽  
Sierra Nevada ◽  
High Frequency ◽  
Variable Number ◽  
B Chromosomes ◽  
Structural Variants ◽  
Satellite Chromosome ◽  
Supernumerary Chromosomes ◽  
Numerical Variation

One hundred bulbs of Ornithogalum umbellatum L. have been analyzed cytogenetically in one natural population collected from the Sierra Nevada of Spain. Three types of plants were identified: (i) diploid plants (2n = 18, 26%); (ii) diploid plants with a variable number of B chromosomes (1–8 B's, 40%); and (iii) polysomic plants (2n = 19–23) with or without B's (34%). B's are of two types: metacentric and acrocentric and are associated with three types of abnormalities: (i) failure of the A chromosomes to move to the poles at anaphase I; (ii) nondisjunction of some A chromosomes at anaphase II; and (iii) the occurrence of tetraploid sporocytes. The B's are isopycnotic, do not associate with the A's, and invariably occur as univalents at first meiosis but show no tendency for elimination. All members of the complement except the satellite chromosome, no. 6, have been detected in a trisomic or a tetrasomic condition. Additionally some unusual structural variants, not present in the diploid standard complement, appear in some polysomic individuals. The polysomic elements are euchromatic, stable, and they do not associate either with normal chromosomes or with B's. The polysomic elements form univalents when they are trisomic and bivalents when tetrasomic. The fact that a high frequency (94%) of the polysomic elements also carry B's suggests that these two forms of numerical variation are interrelated in origin. Key words: Ornithogalum umbellatum, polysomy, supernumerary chromosomes.

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