scholarly journals Supernumerary Chromosomes in the Marsupial Schoinobates Volans (Kerr)

1965 ◽  
Vol 18 (5) ◽  
pp. 1081 ◽  
Author(s):  
DL Hayman ◽  
PG Martin
Keyword(s):  
B Chromosomes ◽  
First Report ◽  
Supernumerary Chromosomes ◽  
Accessory Chromosomes

The presence of special chromosomes which are additional to, and different from, the normal chromosomes, has been reported in many organisms, particularly in plants (Muntzing 1958). These are variously described as B chromosomes, supernumerary chromosomes, or accessory chromosomes. This communication describes the demonstration of these chromosomes in the greater glider, Schoinobates vo"lans (Kerr). We believe this to be the first report of supernumerary chromosomes in a mammal.

Occurrence and Origin of Supernumerary Chromosomes in Partamona (Hymenoptera: Apidae: Meliponini)

2016 ◽  
Vol 150 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Diana P. Machado ◽  
Elder A. Miranda ◽  
Mariana C. Dessi ◽  
Camila P. Sabadini ◽  
Marco A. Del Lama
Keyword(s):  
High Frequency ◽  
Scar Marker ◽  
Sequence Data ◽  
Low Frequency ◽  
B Chromosomes ◽  
First Report ◽  
Supernumerary Chromosomes

Samples from 861 colonies of 12 Partamona species from 125 Brazilian localities were analysed for a SCAR marker specific to the B chromosomes of P. helleri. We identified the SCAR marker in 6 of the 12 species analysed, including 2 (P. gregaria and P. chapadicola) from the pearsoni clade. This is the first report on the presence of this marker in Partamona species that are not included in the cupira clade, which indicates that the B chromosomes probably are more widespread in this genus than previously thought. The analysis revealed a high frequency of the SCAR marker in the samples of P. helleri (0.47), P. cupira (0.46), and P. rustica (0.29), and a low frequency in P. aff. helleri (0.06). The frequency of the marker in P. helleri was correlated with the latitude of the sampling locality, decreasing from north to south. Sequence data on the SCAR marker from 50 individuals of the 6 species in which the presence of this marker was shown revealed a new scenario for the origin of the B chromosomes in Partamona.

Structural hybridity and supernumerary chromosomes in a diploid Tradescantia hirsuticaulis

1975 ◽  
Vol 53 (5) ◽  
pp. 456-465 ◽  
Author(s):  
C. C. Chinnappa
Keyword(s):  
Reciprocal Translocation ◽  
Cytological Study ◽  
B Chromosomes ◽  
The Other ◽  
Meiotic Pairing ◽  
Structural Hybridity ◽  
Supernumerary Chromosomes

Cytological study of a diploid (2n = 12) population of Tradescantia hirsuticaulis Small from Stone Mountain, Georgia, revealed striking variation in four plants growing in a cluster, indicating that they constitute different genotypes. The occurrence of B chromosomes, fragments, and aneusomaty in the plants is associated with structural hybridity in the chromosomes. Two plants were homozygotes with simple meiotic pairing, one was heterozygous for a reciprocal translocation, and the other was a heterozygote for two interchanges as well as for inversions. The behavior and the origin of B chromosomes, fragments, and structural hybridity are discussed.

Chromosomal Characterization of Armored CatfishHarttialongipinna(Siluriformes, Loricariidae): First Report of B Chromosomes in the Genus

2012 ◽  
Vol 29 (9) ◽  
pp. 604-609 ◽  
Author(s):  
Daniel Rodrigues Blanco ◽  
Marcelo Ricardo Vicari ◽  
Roberto Ferreira Artoni ◽  
Josiane Baccarin Traldi ◽  
Orlando Moreira-Filho
Keyword(s):  
B Chromosomes ◽  
First Report

Meiotic stability of B chromosomes and production of macrospermatids in Aiolopus strepens (Orthoptera: Acrididae)

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 5-10 ◽  
Author(s):  
J. A. Suja ◽  
C. Garcia de la Vega ◽  
J. S. Rufas
Keyword(s):  
Key Words ◽  
Natural Populations ◽  
B Chromosomes ◽  
Supernumerary Chromosomes ◽  
Mitotic Instability ◽  
Meiotic Stability ◽  
Intercellular Connections

Four males from several Spanish natural populations of Aiolopus strepens were found to carry B chromosomes. These are short and acrocentric and are identical in the different individuals. They show mitotic instability and meiotic stability. When present in odd numbers one unpaired B is generally observed, while in even numbers they usually form bivalents. In no case were lagging B's observed. B chromosomes do not affect nucleolar expression. A significant increase in the number of macrospermatids is found in individuals with B's. This is more pronounced in follicles containing odd numbers of supernumerary chromosomes. A possible explanation based on an assumed influence of B univalents on the maintenance of intercellular connections is discussed. Key words: B chromosomes, spermiogenesis, insect cytogenetics.

scholarly journals Origin of B chromosomes in Characidium alipioi (Characiformes, Crenuchidae) and its relationship with supernumerary chromosomes in other Characidium species

2017 ◽  
Vol 11 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Érica Alves Serrano ◽  
Ricardo Utsunomia ◽  
Patrícia Sobrinho Scudeller ◽  
Claudio Oliveira ◽  
Fausto Foresti
Keyword(s):  
B Chromosomes ◽  
Supernumerary Chromosomes

scholarly journals Molecular analysis of Drosophila melanogaster B chromosomes reveals their origin, composition, and structure

2018 ◽  
Author(s):  
Stacey L. Hanlon ◽  
Danny E. Miller ◽  
Salam Eche ◽  
R. Scott Hawley
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Analysis ◽  
Model Organism ◽  
B Chromosome ◽  
B Chromosomes ◽  
Individual Species ◽  
Satellite Repeat ◽  
Supernumerary Chromosomes ◽  
Laboratory Stock ◽  
Composition And Structure

ABSTRACTThe number of chromosomes carried by an individual species is one of its defining characteristics. Some species, however, can also carry supernumerary chromosomes referred to as B chromosomes. B chromosomes were recently identified in a laboratory stock of Drosophila melanogaster—an established model organism with a wealth of genetic and genomic resources—enabling us to subject them to extensive molecular analysis. We isolated the B chromosomes by pulsed-field gel electrophoresis and determined their composition through next-generation sequencing. Although these B chromosomes carry no known euchromatic sequence, they are rich in transposable elements and long arrays of short nucleotide repeats, the most abundant being the uncharacterized AAGAT satellite repeat. Fluorescent in-situ hybridization on metaphase chromosome spreads revealed this repeat is located on Chromosome 4, strongly suggesting the origin of the B chromosomes is Chromosome 4. Cytological and quantitative comparisons of signal intensity between Chromosome 4 and the B chromosomes supports the hypothesis that the structure of the B chromosome is an isochromosome. We also report the identification of a new B chromosome variant in a related laboratory stock. This B chromosome has a similar repeat signature as the original but is smaller and much less prevalent. We examined additional stocks with similar genotypes and did not find B chromosomes, but did find these stocks lacked the AAGAT satellite repeat. Our molecular characterization of D. melanogaster B chromosomes is the first step towards understanding how supernumerary chromosomes arise from essential chromosomes and what may be necessary for their stable inheritance.

scholarly journals B Chromosomes in Free-Living Flatworms of the Genus Macrostomum (Platyhelminthes, Macrostomorpha)

2021 ◽  
Vol 22 (24) ◽  
pp. 13617
Author(s):  
Kira S. Zadesenets ◽  
Nikolay B. Rubtsov
Keyword(s):  
Genome Duplication ◽  
Natural Populations ◽  
B Chromosome ◽  
Laboratory Culture ◽  
B Chromosomes ◽  
Free Living ◽  
Transmission Rates ◽  
Supernumerary Chromosomes

B chromosomes (Bs) or supernumerary chromosomes are extra chromosomes in the species karyotype that can vary in its copy number. Bs are widespread in eukaryotes. Usually, the Bs of specimens collected from natural populations are the object of the B chromosome studies. We applied another approach analyzing the Bs in animals maintained under the laboratory conditions as lines and cultures. In this study, three species of the Macrostomum genus that underwent a recent whole-genome duplication (WGD) were involved. In laboratory lines of M. lignano and M. janickei, the frequency of Bs was less than 1%, while in the laboratory culture of M. mirumnovem, it was nearer 30%. Their number in specimens of the culture varied from 1 to 14. Mosaicism on Bs was discovered in parts of these animals. We analyzed the distribution of Bs among the worms of the laboratory cultures during long-term cultivation, the transmission rates of Bs in the progeny obtained from crosses of worms with different numbers of Bs, and from self-fertilized isolated worms. The DNA content of the Bs in M. mirumnovem was analyzed with the chromosomal in situ suppression (CISS) hybridization of microdissected DNA probes derived from A chromosomes (As). Bs mainly consisted of repetitive DNA. The cytogenetic analysis also revealed the divergence and high variation in large metacentric chromosomes (LMs) containing numerous regions enriched for repeats. The possible mechanisms of the appearance and evolution of Bs and LMs in species of the Macrostomum genus were also discussed.

The true identity of Marshallia grandiflora, an extinct species, and the description of Marshallia pulchra (Asteraceae, Helenieae, Marshalliinae)

Phytotaxa ◽  
2020 ◽  
Vol 447 (1) ◽  
pp. 1-15 ◽  
Author(s):  
WESLEY M. KNAPP ◽  
DERICK B. POINDEXTER ◽  
ALAN S. WEAKLEY
Keyword(s):  
North Carolina ◽  
North America ◽  
Endemic Species ◽  
B Chromosomes ◽  
Sister Species ◽  
Blue Ridge ◽  
Extinct Species ◽  
First Report ◽  
New Name ◽  
Cytological Data

Marshallia grandiflora (Asteraceae, Helenieae, Marshalliinae) is recognized as the 53rd extinct species to North America, and an endemic species of the Blue Ridge physiographic province of North Carolina. A new name, Marshallia pulchra, is provided for the more broadly ranging species that has been confounded with and generally considered conspecific with M. grandiflora. Morphologic and biogeographic data clearly separates two species within the previous concept of M. grandiflora. Marshallia grandiflora and M. pulchra are compared with their sister species, M. legrandii. Cytological data is given for M. legrandii, including the first report of B-chromosomes in the genus.

Chromosome numbers of some North American species of Artemisia (Asteraceae)

1988 ◽  
Vol 66 (4) ◽  
pp. 672-676 ◽  
Author(s):  
A. E. Stahevitch ◽  
W. A. Wojtas
Keyword(s):  
United States ◽  
Chromosome Number ◽  
Chromosome Numbers ◽  
The United States ◽  
North American Species ◽  
First Report ◽  
Supernumerary Chromosomes ◽  
Chromosomal Races ◽  
First Time ◽  
Ecological Differences

Chromosome number determinations are reported for 58 accessions, comprising 13 native and introduced taxa of Artemisia found in Canada and the United States. Chromosome numbers observed were n = 8, 9, 18, and 27. A chromosome number of 2n = 18 is the first report for A. pacifica Nutt. A new tetraploid cytotype (2n = 36) was found in A. frigida Willd. Supernumerary chromosomes (n = 9 + 3) and mixoploidy (n = 18, 36) were also observed in this taxon for the first time. Heteroploidy was present in several species. In some taxa, morphological or ecological differences between the chromosomal races were detected; in other cases no differences were noted. Karylogical and phylogenetic evidence is presented for the original chromosome number in Artemisia having been x = 9.

scholarly journals The B Chromosomes of Prochilodus lineatus (Teleostei, Characiformes) Are Highly Enriched in Satellite DNAs

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1527
Author(s):  
José Henrique Forte Stornioli ◽  
Caio Augusto Gomes Goes ◽  
Rodrigo Milan Calegari ◽  
Rodrigo Zeni dos Santos ◽  
Leonardo Moura Giglio ◽  
...  
Keyword(s):  
Repetitive Dna ◽  
Fish Species ◽  
Satellite Dna ◽  
B Chromosomes ◽  
Entire Population ◽  
Satellite Dnas ◽  
Prochilodus Lineatus ◽  
Supernumerary Chromosomes ◽  
Morphological Variants ◽  
First Time

B or supernumerary chromosomes are dispensable elements that are widely present in numerous eukaryotes. Due to their non-recombining nature, there is an evident tendency for repetitive DNA accumulation in these elements. Thus, satellite DNA plays an important role in the evolution and diversification of B chromosomes and can provide clues regarding their origin. The characiform Prochilodus lineatus was one of the first discovered fish species bearing B chromosomes, with all populations analyzed so far showing one to nine micro-B chromosomes and exhibiting at least three morphological variants (Ba, Bsm, and Bm). To date, a single satellite DNA is known to be located on the B chromosomes of this species, but no information regarding the differentiation of the proposed B-types is available. Here, we characterized the satellitome of P. lineatus and mapped 35 satellite DNAs against the chromosomes of P. lineatus, of which six were equally located on all B-types and this indicates a similar genomic content. In addition, we describe, for the first time, an entire population without B chromosomes.

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