scholarly journals CHROMOSOMAL ANALYSIS OF PEROMYSCUS GRATUS (CRICETIDAE) OF TECAMACHALCO, PUEBLA, MEXICO

2020 ◽  
Vol 13 ◽  
Author(s):  
Jesús Martínez-Vázquez ◽  
María De los Ángeles Vela-Montero ◽  
Rosa María González-Monroy
Keyword(s):  
Bone Marrow ◽  
Banding Pattern ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Sex Chromosome ◽  
Chromosomal Analysis ◽  
Barium Hydroxide ◽  
Chromosome X ◽  
Fundamental Number ◽  
Chromosomal Banding

<p>The description was made of the karyotype of <em>Peromyscus gratus</em> (Cricetidae) in the municipality of Tecamachalco, Puebla. Performing the technique of bone marrow extraction, in the obtention of chromosome, G bands was used Trypsin and for C bands a Barium Hydroxide solution was employed. <em>P</em>. <em>gratus</em> presents a diploid number of 2n = 48 and a fundamental number of NF = 54, the autosomes correspond to one metacentric, one submetacentric, two subtelocentric and 19 pairs telocentric from large to small. The sex chromosome X was subtelocentric and the Y was submetacentric unlike other populations of the species. The chromosomal banding pattern G was obtained. As for chromosome C banding, it was found that the constitutive heterochromatin was in the centromeric regions of the chromosomes.</p>

scholarly journals Comparative cytogenetics of two species of Dermanura (Chiroptera, Phyllostomidae) in Midwestern Brazil

2021 ◽  
Vol 15 (2) ◽  
pp. 89-99
Author(s):  
Ricardo Firmino de Sousa ◽  
Paulo Cesar Venere ◽  
Karina de Cassia Faria
Keyword(s):  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Sex Chromosome ◽  
Type System ◽  
Pericentromeric Region ◽  
Morphological Characters ◽  
Comparative Cytogenetics ◽  
Taxonomic Implications ◽  
Sex Chromosome System ◽  
First Time

Dermanura Gervais, 1856 is represented by small frugivorous bats of the Stenodermatinae subfamily. The taxonomy of this group presents controversies and has been subject to changes, especially since the morphological characters evaluated have left gaps that are difficult to fill regarding good species characterization. Previous studies performed in Dermanura cinerea Gervais, 1856 found that the karyotype of this species has a diploid number of chromosomes equal to 30 and 56 autosomal arms. The objective of the present study was to describe, for the first time, the karyotypes of the species Dermanura anderseni (Osgood, 1916) and Dermanura gnoma (Handley, 1987) based on classical cytogenetic markers. For both species, the diploid number found was 2n = 30 and NFa = 56. Two pairs of chromosomes showed markings of the nucleolus organizing regions (AgNORs) in the species D. anderseni and only one pair in D. gnoma, differing from what has already been described for D. cinerea. The two species analyzed here also showed differences in the sex chromosome system, with D. gnoma showing a neo-XY type system while in D. anderseni the classic XY sexual system was observed. In both species, visualization of the constitutive heterochromatin occurred in the pericentromeric region of all chromosomes, as well as in the short arms of the subtelocentric chromosomes. The present work represents an important expansion of karyotypic information for the subfamily Stenodermatinae, bringing chromosomal features that are possible to use in the taxonomic implications of the group.

The karyotype of Sorex arcticus maritimensis (Insectivora, Soricidae) and its systematic implications

1988 ◽  
Vol 66 (9) ◽  
pp. 1968-1972 ◽  
Author(s):  
V. T. Volobouev ◽  
C. G. van Zyll de Jong
Keyword(s):  
Morphometric Analysis ◽  
Banding Pattern ◽  
Diploid Number ◽  
Sorex Araneus ◽  
Exact Nature ◽  
Full Understanding ◽  
Monophyletic Origin ◽  
Fundamental Number ◽  
First Time

The chromosomes of Sorex arcticus maritimensis are described for the first time and their banding pattern (R- and C-bands) compared with those of Sorex araneus. The results provide further evidence for the monophyletic origin of the araneus–arcticus group and clearly indicate that the primary mechanisms of chromosomal reorganization in this group have been Robertsonian and tandem translocations. The basic karyotype of S. a. maritimensis was found to differ from that of S. a. arcticus in having a different fundamental number (34 vs. 38) but the same diploid number. A full understanding of the karyotypic differences between these taxa requires further work. Whatever the exact nature of the differences, they increase the likelihood of an independent specific status for S. a. maritimensis as suggested by the results of an earlier morphometric analysis.

scholarly journals Karyotypic analysis in species of the genus Dasyprocta (Rodentia: Dasyproctidae) found in Brazilian Amazon

2003 ◽  
Vol 75 (1) ◽  
pp. 55-69 ◽  
Author(s):  
ROSEMAR S. L. RAMOS ◽  
WILLIAM G. VALE ◽  
FÁTIMA L. ASSIS
Keyword(s):  
Bone Marrow ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Block Size ◽  
Chromosomal Polymorphism ◽  
Pericentromeric Region ◽  
Brazilian Amazon ◽  
Spleen Cells ◽  
Karyotypic Analysis ◽  
Peripheral Blood Culture

A total of 30 animals of the genus Dasyprocta were cytogenetically studied. They belong to the following species: D. prymnolopha (N=20), D. leporina (N=6), D. fuliginosa (N=1) and Dasyprocta sp. (N=3) (Dasyproctidae, Hystricognathi). Cell suspensions were obtained by peripheral blood culture, besides bone marrow and spleen cells, from D. prymnolopha and D. leporina. The diploid number was 64/65 for all samples. The karyotypes showed similarity, and chromosomal polymorphism was not detected by Giemsa conventional staining and G banding. The constitutive heterochromatin distribution at the pericentromeric region of all the chromosomes was similar in all species. D. prymnolopha, D. leporina and Dasyprocta sp. presented variation in the heterochromatical block size at one of the homologues of the A18 pair. D. fuliginosa presented the heterochromatin uniformly distributed in all chromosomes. There was not variation in the NORs pattern in the species studied.

scholarly journals Chromosomal analysis of Centromochlus heckelii (Siluriformes: Auchenipteridae), with a contribution to Centromochlus definition

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Samantha Kowalski ◽  
Leonardo Marcel Paiz ◽  
Maelin da Silva ◽  
Amanda de Souza Machado ◽  
Eliana Feldberg ◽  
...  
Keyword(s):  
River Basin ◽  
Chromosome Pair ◽  
Diploid Number ◽  
Sex Chromosome ◽  
Chromosomal Analysis ◽  
Amazon River Basin ◽  
Terminal Position ◽  
Chromosomal Markers ◽  
Sex Chromosome System ◽  
Acrocentric Chromosomes

ABSTRACT Historically, there are divergences in the species allocation between Centromochlus and Tatia. This study aimed to generate the first cytogenetic data about Centromochlus and, by analyzing a population of Centromochlus heckelii from the Amazon River basin, to contribute as evidence to a historical taxonomic dilemma. Diploid number of 46 chromosomes and a heteromorphic pair was found in the female karyotypes, thus characterizing a ZZ/ZW sex chromosome system. Pale blocks of heterochromatin were located in centromeric regions of some chromosomes; however, the exclusive female chromosome (W) is almost entirely heterochromatic. AgNORs were detected in terminal position on the short arms of one acrocentric pair in males and two chromosome pairs in females, the acrocentric plus the sex chromosome pair. Notable differences between Centromochlus heckelii and previous data about species of Tatia are: lower diploid number, presence of a sex chromosome system and multiple AgNORs in Centromochlus, while species of Tatia have simple AgNORs and the absence of acrocentric chromosomes. Results in this study show that chromosomal markers could contribute as evidence to taxonomic delimitation studies.

scholarly journals Interspecific chromosomal divergences in the genus Characidium (Teleostei: Characiformes: Crenuchidae)

2010 ◽  
Vol 8 (1) ◽  
pp. 77-86 ◽  
Author(s):  
José Carlos Pansonato Alves ◽  
Luiz Ricardo de Souza Paiva ◽  
Claudio Oliveira ◽  
Fausto Foresti
Keyword(s):  
Chromosome Pair ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Sex Chromosome ◽  
Way Of Life ◽  
Geographical Isolation ◽  
Relevant Role ◽  
Sex Chromosome System ◽  
Morphological Differences ◽  
First Time

Karyotypes of seven fish species of the genus Characidium, three of them studied for the first time, were characterized using conventional cytogenetic techniques (Giemsa staining, Ag-NOR, and C-banding). All species presented a diploid number of 2n=50, with only metacentric and submetacentric chromosomes, as observed in all Characidium species studied. In two species cells with one to three B chromosomes were observed. All species analyzed have a single NOR-bearing chromosome pair with morphological differences among them. Characidium cf. zebra shows heterochromatic blocks restricted to the pericentromeric regions of all chromosomes denoting the absence of a sex chromosome system. On the other hand, the species Characidium lanei, C. pterostictum, C. lauroi, C. oiticicai, C. schubarti, and Characidium sp., besides presenting pericentromeric heterochromatic blocks, exhibited large interstitial and/or terminal heterochromatic blocks, and a ZZ/ZW sex chromosome system. The constitutive heterochromatin seems to play a relevant role in the chromosome differentiation process of the studied species, mainly in relation to the sex chromosomes. The geographical isolation of the rivers in which the species were sampled, associated with their way of life restricted to headwaters environments, may have favored the process of fixation of different karyotypes found in each of the analyzed species.

scholarly journals Comparative cytogenetics of two species of Dermanura (Chiroptera, Phyllostomidae) in Midwestern Brazil

2021 ◽  
Vol 15 (2) ◽  
pp. 89-99
Author(s):  
Ricardo Firmino de Sousa ◽  
Paulo Cesar Venere ◽  
Karina de Cassia Faria
Keyword(s):  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Sex Chromosome ◽  
Type System ◽  
Pericentromeric Region ◽  
Morphological Characters ◽  
Comparative Cytogenetics ◽  
Taxonomic Implications ◽  
Sex Chromosome System ◽  
First Time

Dermanura Gervais, 1856 is represented by small frugivorous bats of the Stenodermatinae subfamily. The taxonomy of this group presents controversies and has been subject to changes, especially since the morphological characters evaluated have left gaps that are difficult to fill regarding good species characterization. Previous studies performed in Dermanura cinerea Gervais, 1856 found that the karyotype of this species has a diploid number of chromosomes equal to 30 and 56 autosomal arms. The objective of the present study was to describe, for the first time, the karyotypes of the species Dermanura anderseni (Osgood, 1916) and Dermanura gnoma (Handley, 1987) based on classical cytogenetic markers. For both species, the diploid number found was 2n = 30 and NFa = 56. Two pairs of chromosomes showed markings of the nucleolus organizing regions (AgNORs) in the species D. anderseni and only one pair in D. gnoma, differing from what has already been described for D. cinerea. The two species analyzed here also showed differences in the sex chromosome system, with D. gnoma showing a neo-XY type system while in D. anderseni the classic XY sexual system was observed. In both species, visualization of the constitutive heterochromatin occurred in the pericentromeric region of all chromosomes, as well as in the short arms of the subtelocentric chromosomes. The present work represents an important expansion of karyotypic information for the subfamily Stenodermatinae, bringing chromosomal features that are possible to use in the taxonomic implications of the group.

scholarly journals Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae)

2000 ◽  
Vol 23 (2) ◽  
pp. 365-369 ◽  
Author(s):  
Edson Luis Maistro ◽  
Claudio Oliveira ◽  
Fausto Foresti
Keyword(s):  
Chromosome Pair ◽  
Chromosome Evolution ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Sao Paulo ◽  
São Paulo ◽  
Robertsonian Translocations ◽  
Fundamental Number ◽  
Astyanax Scabripinnis ◽  
The Difference

Among four specimens of Astyanax scabripinnis sympatrically collected from the Tamanduá stream (State of São Paulo, Brazil), three, named cytotype I, had 2n = 50 chromosomes (6M + 26SM + 4ST + 14A) and a fundamental number (FN) of 86, and one specimen, named cytotype II, had 2n = 48 chromosomes (6M + 28SM + 4ST + 10A) and FN = 86. Besides the difference in diploid number, the cytotypes showed a clear difference in the distribution of constitutive heterochromatin. One NOR-bearing chromosome pair was detected in both cytotypes and one specimen of cytotype I had multiple NORs (tree chromosome pairs). Robertsonian translocations and an increase or loss of heterochromatin are proposed to explain the karyotypic divergence observed. Some aspects related to the chromosome evolution of Astyanax scabripinnis are discussed.

scholarly journals Chromosomal relationships among the native rodents (Cricetidae: Oryzomyini) of the Galápagos Islands, Ecuador

Therya ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 317-329
Author(s):  
Robert C. Dowler ◽  
Marcia A. Revelez
Keyword(s):  
Diploid Number ◽  
Galapagos Islands ◽  
Ancestral Karyotype ◽  
Galápagos Islands ◽  
Robertsonian Fusion ◽  
Fundamental Number ◽  
Tandem Fusion ◽  
Extant Species ◽  
Chromosomal Banding ◽  
Species Descriptions

Although the Galápagos Islands are recognized for their contribution to our understanding of evolutionary theory and have received the attention of scientists for over 185 years, our understanding of the native rodents there has been minimal relative to many other groups of organisms.  Much of what we knew through most of the 20th century was based solely on species descriptions.  Chromosome data has been limited to only Nesoryzomys narboroughi (2n = 32, FN (number of autosomal arms) = 50) and Aegialomys galapagoensis (2n = 56; FN = 58).  We present the karyotypes of the only remaining extant species in the genus, N. swarthi (2n = 56; FN = 54) and N. fernandinae (2n = 44; FN = 54).  Chromosomal banding reveals that extensive rearrangement has occurred within Nesoryzomys, including Robertsonian fusion and tandem fusion events but these alone cannot account for the diverse diploid numbers found within the genus.  We propose that 1) N. swarthi represents the ancestral karyotype for the genus, similar to A. galapagoensis, 2) N. swarthi and N. fernandinae share the same fundamental number, suggesting divergence by Robertsonian fusions, and 3) N. narboroughi has the most derived karyotype, based on banding morphology and low diploid number.

Diversity and Karyotypic Evolution in the Genus Neacomys (Rodentia, Sigmodontinae)

2015 ◽  
Vol 146 (4) ◽  
pp. 296-305 ◽  
Author(s):  
Willam O. da Silva ◽  
Julio C. Pieczarka ◽  
Rogério V. Rossi ◽  
Horacio Schneider ◽  
Iracilda Sampaio ◽  
...  
Keyword(s):  
Molecular Phylogeny ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Chromosomal Evolution ◽  
The Other ◽  
Karyotypic Evolution ◽  
Drastic Reduction ◽  
Ancestral Species ◽  
Pericentric Inversions ◽  
Amazonian Region

Neacomys (Sigmodontinae) comprises 8 species mainly found in the Amazonian region. We describe 5 new karyotypes from Brazilian Amazonia: 2 cytotypes for N. paracou (2n = 56/FNa = 62-66), 1 for N. dubosti (2n = 64/FNa = 68), and 2 for Neacomys sp. (2n = 58/FNa = 64-70), with differences in the 18S rDNA. Telomeric probes did not show ITS. We provide a phylogeny using Cytb, and the analysis suggests that 2n = 56 with a high FNa is ancestral for the genus, as found in N. paracou, being retained by the ancestral forms of the other species, with an increase in 2n occurring independently in N. spinosus and N. dubosti. Alternatively, an increase in 2n may have occurred in the ancestral taxon of the other species, followed by independent 2n-reduction events in Neacomys sp. and in the ancestral species of N. tenuipes, N. guianae, N. musseri, and N. minutus. Finally, a drastic reduction event in the diploid number occurred in the ancestral species of N. musseri and N. minutus which exhibit the lowest 2n of the genus. The karyotypic variations found in both intra- and interspecific samples, associated with the molecular phylogeny, suggest a chromosomal evolution with amplification/deletion of constitutive heterochromatin and rearrangements including fusions, fissions, and pericentric inversions.

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